{"id":1071,"date":"2025-05-21T20:28:05","date_gmt":"2025-05-21T12:28:05","guid":{"rendered":"https:\/\/www.hyy.net\/?p=1071"},"modified":"2025-05-21T20:28:05","modified_gmt":"2025-05-21T12:28:05","slug":"asp-net-core-razor-pages-in-action-8-%e5%a4%84%e7%90%86%e6%95%b0%e6%8d%ae","status":"publish","type":"post","link":"https:\/\/diji.net\/?p=1071","title":{"rendered":"ASP.NET Core Razor Pages in Action 8 \u5904\u7406\u6570\u636e"},"content":{"rendered":"

ASP.NET Core Razor Pages in Action 8 \u5904\u7406\u6570\u636e<\/p>\n

\u672c\u7ae0\u6db5\u76d6<\/h2>\n

\u2022 \u4e86\u89e3 Entity Framework Core \u7684\u4ef7\u503c\u53ca\u5176\u5de5\u4f5c\u539f\u7406
\n\u2022 \u4f7f\u7528 Entity Framework Core \u7ba1\u7406\u6570\u636e\u5e93\u67b6\u6784
\n\u2022 \u4f7f\u7528 Entity Framework Core \u67e5\u8be2\u548c\u7ba1\u7406\u6570\u636e
\n\u2022 \u642d\u5efa\u4e0e Entity Framework Core \u914d\u5408\u4f7f\u7528\u7684 Razor Pages \u5e76\u6539\u8fdb\u8f93\u51fa\u7684\u57fa\u67b6<\/p>\n

\u5230\u76ee\u524d\u4e3a\u6b62\uff0c\u6211\u4eec\u5df2\u96c6\u4e2d\u7cbe\u529b\u63a2\u7d22 Razor Pages \u6846\u67b6\u7684\u529f\u80fd\u4ee5\u53ca\u5b83\u4eec\u5982\u4f55\u751f\u6210 HTML\u3002\u672c\u7ae0\u4e0e\u6b64\u7565\u6709\u4e0d\u540c\uff0c\u800c\u662f\u91cd\u70b9\u4ecb\u7ecd\u79f0\u4e3a Entity Framework Core \uff08EF Core\uff09 \u7684\u4e0d\u540c\u6846\u67b6\u3002<\/p>\n

\u9664\u4e86\u6700\u7b80\u5355\u7684\u4ea4\u4e92\u5f0f Web \u5e94\u7528\u7a0b\u5e8f\u4e4b\u5916\uff0c\u6240\u6709\u5e94\u7528\u7a0b\u5e8f\u90fd\u4f9d\u8d56\u4e8e\u6570\u636e\u7684\u6301\u4e45\u6027\u548c\u68c0\u7d22\u6765\u652f\u6301\u5176\u52a8\u6001\u5185\u5bb9\u3002\u8be5\u6570\u636e\u901a\u5e38\u5b58\u50a8\u5728\u67d0\u79cd\u5173\u7cfb\u6570\u636e\u5e93\u4e2d\u5e76\u4ece\u4e2d\u68c0\u7d22\u3002\u5728\u8fc7\u53bb\uff0c\u7ba1\u7406\u8fd9\u4e9b\u6570\u636e\u8bbf\u95ee\u4efb\u52a1\u6240\u9700\u7684\u4ee3\u7801\u975e\u5e38\u91cd\u590d\u3002\u6bcf\u6b21\u8981\u4e0e\u6570\u636e\u5e93\u901a\u4fe1\u65f6\uff0c\u60a8\u90fd\u9700\u8981\u5728\u4ee3\u7801\u4e2d\u5efa\u7acb\u4e0e\u6570\u636e\u5e93\u7684\u8fde\u63a5\uff0c\u5b9a\u4e49\u8981\u6267\u884c\u7684 SQL \u67e5\u8be2\uff0c\u6267\u884c\u8be5\u67e5\u8be2\uff0c\u5e76\u5728\u4f4e\u7ea7\u5bb9\u5668\uff08\u5982 Recordset\u3001DataTable \u6216 DataReader\uff09\u4e2d\u6355\u83b7\u8fd4\u56de\u7684\u6570\u636e\uff0c\u7136\u540e\u5c06\u6570\u636e\u5904\u7406\u4e3a\u5e94\u7528\u7a0b\u5e8f\u53ef\u4ee5\u4f7f\u7528\u7684\u67d0\u79cd\u5f62\u5f0f\u3002EF Core \u7684\u4e3b\u8981\u4f5c\u7528\u662f\u5c06\u5176\u62bd\u8c61\u51fa\u6765\uff0c\u56e0\u6b64\u60a8\u53ef\u4ee5\u4e13\u6ce8\u4e8e\u7f16\u5199\u4ee3\u7801\u6765\u5904\u7406\u6570\u636e\uff0c\u800c\u4e0d\u662f\u7f16\u5199\u4ee3\u7801\u4ece\u6570\u636e\u5e93\u4e2d\u68c0\u7d22\u6570\u636e\u3002\u672c\u7ae0\u901a\u8fc7\u5176\u4e0a\u4e0b\u6587\uff08\u6d3e\u751f\u81ea DbContext \u7684\u5bf9\u8c61\uff09\u4f7f\u7528 EF Core \u6267\u884c\u57fa\u672c\u7684 CRUD\u4f5c\uff0c\u8be5\u4e0a\u4e0b\u6587\u662f\u4f7f\u7528 EF Core \u7684\u6838\u5fc3\u3002<\/p>\n

EF Core \u7684\u529f\u80fd\u6bd4\u4ec5\u4ec5\u66ff\u6362\u5bf9\u6570\u636e\u5e93\u6267\u884c\u547d\u4ee4\u6240\u9700\u7684\u6837\u677f\u4ee3\u7801\u8981\u5f3a\u5927\u5f97\u591a\u3002\u6211\u4eec\u5c06\u63a2\u8ba8\u5982\u4f55\u4f7f\u7528\u5b83\u4ece\u5e94\u7528\u7a0b\u5e8f\u6a21\u578b\u751f\u6210\u6570\u636e\u5e93\uff0c\u7136\u540e\u901a\u8fc7\u79f0\u4e3a migrations \u7684\u529f\u80fd\u4f7f\u6570\u636e\u5e93\u67b6\u6784\u4e0e\u6a21\u578b\u4fdd\u6301\u540c\u6b65\u3002\u6211\u4eec\u8fd8\u5c06\u4e86\u89e3 EF Core \u7528\u4e8e\u5c06\u6a21\u578b\u6620\u5c04\u5230\u6570\u636e\u5e93\u7684\u7ea6\u5b9a\uff0c\u4ee5\u53ca\u5982\u4f55\u6839\u636e\u9700\u8981\u4f7f\u7528\u914d\u7f6e\u6765\u81ea\u5b9a\u4e49\u8fd9\u4e9b\u6620\u5c04\u3002<\/p>\n

\u672c\u7ae0\u8fd8\u5c06\u4ecb\u7ecd\u4e00\u4e2a\u79f0\u4e3a\u57fa\u67b6\u7684\u529f\u80fd\u3002\u6b64\u529f\u80fd\u7ed3\u5408\u4e86\u60a8\u7684\u5e94\u7528\u7a0b\u5e8f\u6a21\u578b\u548c\u6570\u636e\u5e93\u77e5\u8bc6\uff0c\u53ef\u4e3a\u6a21\u578b\u4e2d\u7684\u7279\u5b9a\u5bf9\u8c61\u5feb\u901f\u751f\u6210\u5de5\u4f5c CRUD \u9875\u9762\u3002\u60a8\u5c06\u4e86\u89e3\u57fa\u67b6\u5de5\u5177\u751f\u6210\u7684\u4ee3\u7801\u7684\u5c40\u9650\u6027\uff0c\u5e76\u4e86\u89e3\u5982\u4f55\u6539\u8fdb\u5b83\u4eec\u4ee5\u7b26\u5408\u6211\u4eec\u5728\u4e0a\u4e00\u7ae0\u4e2d\u4ecb\u7ecd\u7684\u4e00\u4e9b\u8f6f\u4ef6\u5de5\u7a0b\u539f\u5219\u3002<\/p>\n

\u5728\u672c\u7ae0\u7ed3\u675f\u65f6\uff0c\u60a8\u5c06\u4e86\u89e3 EF Core \u7684\u89d2\u8272\uff0c\u4ee5\u53ca\u5982\u4f55\u4f7f\u7528\u5b83\u5bf9\u5173\u7cfb\u6570\u636e\u5e93\u6267\u884c\u547d\u4ee4\u3001\u7ba1\u7406\u8be5\u6570\u636e\u5e93\u7684\u67b6\u6784\u4ee5\u53ca\u751f\u6210 CRUD \u9875\u9762\u3002\u7136\u800c\uff0cEF Core \u662f\u4e00\u4e2a\u5f88\u5927\u7684\u8bdd\u9898;\u5728\u672c\u4e66\u4e2d\uff0c\u6211\u4eec\u53ea\u89e6\u53ca\u4e86\u5b83\u7684\u529f\u80fd\u548c\u4f7f\u7528\u7684\u76ae\u6bdb\u3002\u4e3a\u4e86\u5145\u5206\u5229\u7528\u8fd9\u4e2a\u51fa\u8272\u7684\u5de5\u5177\uff0c\u60a8\u5e94\u8be5\u83b7\u53d6 Jon P. Smith \uff08http:\/\/mng.bz\/vXr4<\/a>\uff09 \u7f16\u5199\u7684\u4f18\u79c0 Entity Framework Core in Action \uff082nd ed.\uff09 \u7684\u526f\u672c\uff0c\u5e76\u53c2\u9605\u5b98\u65b9\u6587\u6863 \uff08https:\/\/docs.microsoft.com\/en-us\/ef\/core\/<\/a>\uff09\u3002<\/p>\n

8.1 \u4ec0\u4e48\u662f Entity Framework Core\uff1f<\/h2>\n

EF Core \u662f\u4e00\u79cd\u5bf9\u8c61\u5173\u7cfb\u6620\u5c04 \uff08ORM\uff09 \u5de5\u5177\u3002\u5b83\u7684\u4f5c\u7528\u662f\u5728\u5bf9\u8c61 \uff08\u5e94\u7528\u7a0b\u5e8f\u6a21\u578b\uff09 \u548c\u5173\u7cfb\u4e16\u754c \uff08\u6570\u636e\u5e93\uff09 \u4e4b\u95f4\u8fdb\u884c\u6620\u5c04\u3002EF Core \u9002\u7528\u4e8e\u8bb8\u591a\u6570\u636e\u5e93\uff0c\u5305\u62ec\u6d41\u884c\u7684 Microsoft SQL Server \u548c MySQL \u6570\u636e\u5e93\u7cfb\u7edf\u3002\u672c\u4e66\u5c06 EF Core \u4e0e SQLite \u7ed3\u5408\u4f7f\u7528\uff0cSQLite \u662f\u4e00\u4e2a\u5f00\u6e90\u3001\u8de8\u5e73\u53f0\u3001\u57fa\u4e8e\u6587\u4ef6\u7684\u6570\u636e\u5e93\u3002\u867d\u7136\u7f3a\u5c11\u8bb8\u591a\u529f\u80fd\uff0c\u4f46\u5728\u66f4\u5f3a\u5927\u7684\u57fa\u4e8e\u670d\u52a1\u5668\u7684\u7cfb\u7edf\u4e2d\u627e\u5230\uff0cSQLite \u6613\u4e8e\u4f7f\u7528\uff0c\u65e0\u9700\u5b89\u88c5\u6216\u914d\u7f6e\uff0c\u5e76\u4e14\u8db3\u4ee5\u6ee1\u8db3\u6211\u4eec\u5c06\u5728\u672c\u7ae0\u4e2d\u63a2\u8ba8\u7684 EF Core \u529f\u80fd\u3002<\/p>\n

8.1.1 \u4e3a\u4ec0\u4e48\u9009\u62e9 EF Core\uff1f<\/h3>\n

\u60a8\u53ef\u4ee5\u4f7f\u7528\u4f4e\u7ea7\u3001\u8001\u5f0f\u7684 ADO.NET API \u6765\u7ba1\u7406\u4e0e\u6570\u636e\u5e93\u7684\u901a\u4fe1\uff0c\u4f46\u6240\u9700\u7684\u4ee3\u7801\u662f\u91cd\u590d\u7684\uff08\u6211\u5df2\u7ecf\u8bf4\u8fc7\u4e86\u5417\uff1f\uff09\u5e76\u4e14\u7f16\u5199\u8d77\u6765\u5f88\u65e0\u804a\u3002\u4e00\u79cd\u89e3\u51b3\u65b9\u6848\u662f\u7f16\u5199\u81ea\u5df1\u7684 helper \u5e93\u4ee5\u51cf\u5c11\u91cd\u590d\u3002\u4f46\u662f\uff0c\u60a8\u5fc5\u987b\u81ea\u5df1\u7ef4\u62a4\u8be5\u4ee3\u7801\u3002\u6570\u636e\u8bbf\u95ee\u5e93\u975e\u5e38\u4e30\u5bcc\uff0c\u9664\u975e\u60a8\u80fd\u627e\u5230\u6539\u8fdb\u73b0\u6709\u4ea7\u54c1\u7684\u65b9\u6cd5\uff0c\u5426\u5219\u5982\u679c\u60a8\u53ea\u9700\u8981\u7ee7\u7eed\u5236\u4f5c Web \u5e94\u7528\u7a0b\u5e8f\uff0c\u90a3\u4e48\u7f16\u5199\u81ea\u5df1\u7684\u5e93\u53ef\u80fd\u4f1a\u6d6a\u8d39\u65f6\u95f4\u3002<\/p>\n

\u4f60\u53ef\u4ee5\u81ea\u7531\u4f7f\u7528\u4efb\u4f55\u4f60\u559c\u6b22\u7684\u5e93\u6765\u7ba1\u7406 Razor Pages \u5e94\u7528\u7a0b\u5e8f\u4e2d\u7684\u6570\u636e\u8bbf\u95ee\uff0c\u90a3\u4e48\u5728\u6240\u6709\u4e30\u5bcc\u7684\u73b0\u6709\u5e93\u4e2d\uff0c\u4e3a\u4ec0\u4e48\u9009\u62e9 EF Core\uff1f\u4f5c\u4e3a .NET \u7684\u4e00\u90e8\u5206\uff0c\u5b83\u5f97\u5230\u4e86\u5f88\u597d\u7684\u652f\u6301\u548c\u6d4b\u8bd5\uff0c\u5e76\u4eab\u6709\u5927\u91cf\u7684\u5b98\u65b9\u6587\u6863\u3002\u9664\u4e86\u5b98\u65b9\u6587\u6863\u4e4b\u5916\uff0c\u8fd8\u6709\u5927\u91cf\u7684\u793e\u533a\u8d21\u732e\uff0c\u4f8b\u5982\u4e66\u7c4d\u3001\u535a\u5ba2\u6587\u7ae0\u548c\u6559\u7a0b\u7f51\u7ad9\uff0c\u5b83\u4eec\u63a2\u7d22\u4e86 EF Core \u66f4\u6df1\u5965\u7684\u529f\u80fd\u53ca\u5176\u6700\u5e38\u89c1\u7684\u5de5\u4f5c\u6d41\u7a0b\u3002\u5982\u679c\u6240\u6709\u5176\u4ed6\u65b9\u6cd5\u90fd\u5931\u8d25\u4e86\uff0c\u5e76\u4e14\u60a8\u96be\u4ee5\u4f7f\u67d0\u4e9b\u5185\u5bb9\u6b63\u5e38\u5de5\u4f5c\uff0c\u5219\u53ef\u4ee5\u5c06\u95ee\u9898\u53d1\u5e03\u5230 EF Core GitHub \u5b58\u50a8\u5e93 \uff08https:\/\/github.com\/dotnet\/efcore\uff09\uff0c\u60a8\u751a\u81f3\u53ef\u4ee5\u4eceEF<\/a> Core\u56e2\u961f\u7684\u4e00\u4f4d\u5f00\u53d1\u4eba\u5458\u90a3\u91cc\u5f97\u5230\u56de\u590d\u3002<\/p>\n

EF Core \u5728 Visual Studio \u4e2d\u63d0\u4f9b\u5de5\u5177\u652f\u6301\uff0c\u53ef\u5e2e\u52a9\u4f60\u6839\u636e\u5e94\u7528\u7a0b\u5e8f\u6a21\u578b\u5feb\u901f\u751f\u6210 CRUD \u9875\u9762\u3002\u867d\u7136\u7ed3\u679c\u5e76\u4e0d\u5b8c\u7f8e\uff0c\u4f46\u5b83\u4eec\u4e3a\u5f00\u53d1\u5e94\u7528\u7a0b\u5e8f\u4e2d\u66f4\u666e\u901a\u7684\u90e8\u5206\u63d0\u4f9b\u4e86\u4e00\u4e2a\u91cd\u8981\u7684\u5f00\u7aef\u3002\u57fa\u67b6\u652f\u6301\u4e5f\u53ef\u4f9b\u975e Visual Studio \u7528\u6237\u4ece\u547d\u4ee4\u884c\u4f7f\u7528\u3002\u60a8\u7a0d\u540e\u5c06\u770b\u5230\u5b83\u7684\u5b9e\u9645\u6548\u679c\u3002<\/p>\n

8.1.2 EF Core \u7684\u5de5\u4f5c\u539f\u7406\u662f\u4ec0\u4e48\uff1f<\/h3>\n

\u5728\u57fa\u672c\u5c42\u9762\u4e0a\uff0cEF Core \u4f1a\u521b\u5efa\u4e00\u4e2a\u6982\u5ff5\u6a21\u578b\uff0c\u8bf4\u660e\u57df\u5bf9\u8c61\u53ca\u5176\u5c5e\u6027\uff08\u5e94\u7528\u7a0b\u5e8f\u6a21\u578b\uff09\u5982\u4f55\u6620\u5c04\u5230\u6570\u636e\u5e93\u4e2d\u7684\u8868\u548c\u5217\u3002\u5b83\u8fd8\u4e86\u89e3\u57df\u5bf9\u8c61\u4e4b\u95f4\u7684\u5173\u8054\uff0c\u5e76\u53ef\u4ee5\u5c06\u8fd9\u4e9b\u5173\u8054\u6620\u5c04\u5230\u6570\u636e\u5e93\u5173\u7cfb\u3002\u5b83\u662f\u5e94\u7528\u7a0b\u5e8f\u7684\u63d2\u5165\u5f0f\u6570\u636e\u5c42\uff0c\u4f4d\u4e8e\u57df\uff08\u56fe 8.1 \u7684\u5de6\u4fa7\uff09\u548c\u6570\u636e\u5b58\u50a8\uff08\u56fe 8.1 \u7684\u53f3\u4fa7\uff09\u4e4b\u95f4\u3002<\/p>\n

<\/p>\n

\u56fe 8.1 EF Core \u4f4d\u4e8e\u5de6\u4fa7\u7684\u57df\u5bf9\u8c61\u548c\u53f3\u4fa7\u7684\u6570\u636e\u5e93\u4e4b\u95f4\uff0c\u5c06\u5bf9\u8c61\u53ca\u5176\u5c5e\u6027\u548c\u5173\u8054\u6620\u5c04\u5230\u6570\u636e\u5e93\u8868\u3001\u5217\u548c\u5173\u7cfb\u3002<\/p>\n

EF Core \u7ba1\u7406\u4e1a\u52a1\u5bf9\u8c61\u4e0e\u6570\u636e\u5b58\u50a8\u4e4b\u95f4\u7684\u901a\u4fe1\u3002\u8bed\u8a00\u96c6\u6210\u67e5\u8be2 \uff08LINQ\uff09 \u5c06\u5e2e\u52a9\u60a8\u5728\u5e94\u7528\u7a0b\u5e8f\u4ee3\u7801\u4e2d\u521b\u5efa\u67e5\u8be2\u89c4\u8303\uff0c\u5e76\u5c06\u8fd9\u4e9b\u89c4\u8303\u63d0\u4f9b\u7ed9 EF Core\u3002EF Core \u5c06 LINQ \u67e5\u8be2\u8f6c\u6362\u4e3a SQL \u547d\u4ee4\uff0cEF Core \u5bf9\u6570\u636e\u5e93\u6267\u884c\u8fd9\u4e9b\u67e5\u8be2\uff0c\u5982\u56fe 8.2 \u6240\u793a\u3002SQL EF \u6838\u5fc3\u751f\u6210\u7684\u662f\u53c2\u6570\u5316\u7684\uff0c\u8fd9\u610f\u5473\u7740\u5b83\u53d7\u5230\u4fdd\u62a4\uff0c\u53ef\u4ee5\u62b5\u5fa1\u6f5c\u5728\u7684 SQL \u6ce8\u5165\u653b\u51fb \uff08http:\/\/mng.bz\/49qj\uff09\u3002\u60a8\u5c06\u5728\u7b2c<\/a> 13 \u7ae0\u4e2d\u66f4\u8be6\u7ec6\u5730\u7814\u7a76 SQL \u6ce8\u5165\u653b\u51fb\uff0c\u5c4a\u65f6\u60a8\u5c06\u4e13\u6ce8\u4e8e\u4fdd\u62a4\u5e94\u7528\u7a0b\u5e8f\u514d\u53d7\u5916\u90e8\u5a01\u80c1\u3002<\/p>\n

<\/p>\n

\u56fe 8.2 EF Core \u5de5\u4f5c\u6d41\uff0c\u83b7\u53d6 LINQ \u67e5\u8be2\uff0c\u5c06\u5176\u8f6c\u6362\u4e3a SQL \u4ee5\u9488\u5bf9\u6570\u636e\u5e93\u6267\u884c\uff0c\u5e76\u4ee5\u53ef\u5728\u5e94\u7528\u7a0b\u5e8f\u4e2d\u4f7f\u7528\u7684\u5f62\u5f0f\u8fd4\u56de\u7ed3\u679c<\/p>\n

\u5982\u679c\u67e5\u8be2\u65e8\u5728\u8fd4\u56de\u6570\u636e\uff0cEF Core \u4f1a\u8d1f\u8d23\u5c06\u6570\u636e\u4ece\u6570\u636e\u5e93\u8f6c\u6362\u4e3a\u57df\u5bf9\u8c61\u3002\u5982\u679c\u60a8\u719f\u6089\u8f6f\u4ef6\u8bbe\u8ba1\u6a21\u5f0f\uff0c\u5219\u5f88\u53ef\u80fd\u5c06\u5176\u8bc6\u522b\u4e3a Repository \u6a21\u5f0f \uff08http:\/\/mng.bz\/QnYv<\/a>\uff09 \u7684\u5b9e\u73b0\u3002<\/p>\n

EF Core \u751f\u6210\u7684 SQL \u53d6\u51b3\u4e8e\u4f60\u4f7f\u7528\u7684\u63d0\u4f9b\u7a0b\u5e8f\u3002\u6bcf\u4e2a\u6570\u636e\u5e93\u7cfb\u7edf\u90fd\u6709\u81ea\u5df1\u7684\u63d0\u4f9b\u7a0b\u5e8f\uff0c\u56e0\u6b64\u7406\u8bba\u4e0a\uff0c\u751f\u6210\u7684 SQL \u5e94\u9488\u5bf9\u7279\u5b9a\u6570\u636e\u5e93\u8fdb\u884c\u4f18\u5316\u3002EF Core \u5c06\u6240\u6709\u8fd9\u4e9b\u9690\u85cf\u5728\u4f60\u7684\u5e94\u7528\u7a0b\u5e8f\u4ee3\u7801\u4e4b\u5916\uff0c\u56e0\u6b64\u5982\u679c\u4f60\u5728\u67d0\u4e2a\u65f6\u5019\u9700\u8981\u66f4\u6539\u63d0\u4f9b\u7a0b\u5e8f\uff0c\u4f60\u7684 LINQ \u67e5\u8be2\u5c06\u65e0\u9700\u4fee\u6539\u5373\u53ef\u5de5\u4f5c\u3002\u867d\u7136\u4ece\u4e00\u4e2a\u5b9e\u9645\u6570\u636e\u5e93\u7cfb\u7edf\u8fc1\u79fb\u5230\u53e6\u4e00\u4e2a\u5b9e\u9645\u6570\u636e\u5e93\u7cfb\u7edf\u7684\u60c5\u51b5\u5728\u73b0\u5b9e\u4e16\u754c\u4e2d\u5f88\u5c11\u89c1\uff0c\u4f46\u5982\u679c\u60a8\u60f3\u5c06\u7269\u7406\u6570\u636e\u5e93\u66ff\u6362\u4e3a\u5185\u5b58\u4e2d\u6570\u636e\u5e93\u4ee5\u8fdb\u884c\u6d4b\u8bd5\uff0c\u5219\u6b64\u529f\u80fd\u4f1a\u66f4\u6709\u7528\u3002<\/p>\n

\u4f7f\u7528 EF Core \u65f6\u91c7\u7528\u7684\u65b9\u6cd5\u79f0\u4e3a\u4ee3\u7801\u4f18\u5148\uff08\u800c\u4e0d\u662f\u6570\u636e\u5e93\u4f18\u5148\uff09\uff0c\u8fd9\u610f\u5473\u7740\u4f60\u5c06\u7cbe\u529b\u96c6\u4e2d\u5728\u5f00\u53d1\u5e94\u7528\u7a0b\u5e8f\u6a21\u578b\u4e0a\uff0c\u5e76\u5141\u8bb8 EF Core \u4f7f\u7528\u8be5\u6a21\u578b\u4f5c\u4e3a\u7ef4\u62a4\u6570\u636e\u5e93\u67b6\u6784\u7684\u57fa\u7840\uff0c\u4f7f\u7528\u79f0\u4e3a\u8fc1\u79fb\u7684\u6982\u5ff5\u3002\u5982\u679c\u6570\u636e\u5e93\u4e0d\u5b58\u5728\uff0cEF Core \u8fd8\u53ef\u4ee5\u521b\u5efa\u6570\u636e\u5e93\u672c\u8eab\u3002EF Core \u4f9d\u8d56\u4e8e\u591a\u4e2a\u7ea6\u5b9a\u5c06\u5bf9\u8c61\u53ca\u5176\u5c5e\u6027\u6620\u5c04\u5230\u6570\u636e\u5e93\u8868\u548c\u5217\u5e76\u521b\u5efa\u5173\u7cfb\u3002\u5728\u4f18\u5316\u57df\u6a21\u578b\u4ee5\u4f7f\u7528 EF Core \u65f6\uff0c\u4f60\u5c06\u63a2\u7d22\u6700\u91cd\u8981\u7684\u7ea6\u5b9a\u3002\u9664\u4e86\u201c\u6b63\u5e38\u5de5\u4f5c\u201d\u7684\u7ea6\u5b9a\u4e4b\u5916\uff0cEF Core \u8fd8\u63d0\u4f9b\u4e86\u5e7f\u6cdb\u7684\u914d\u7f6e\u9009\u9879\uff0c\u4f7f\u4f60\u80fd\u591f\u63a7\u5236\u6a21\u578b\u6620\u5c04\u5230\u6570\u636e\u5e93\u4e2d\u7684\u8868\u548c\u5217\u7684\u65b9\u5f0f\u3002<\/p>\n

8.1.3 \u7ba1\u7406\u5173\u7cfb<\/h3>\n

\u5173\u7cfb\u6570\u636e\u5e93\u7cfb\u7edf\u7684\u5b58\u5728\u53ea\u662f\u4e3a\u4e86\u65b9\u4fbf\u5904\u7406\u5f7c\u6b64\u76f8\u5173\u7684\u6570\u636e\u96c6\u3002\u5728\u6570\u636e\u5e93\u4e2d\uff0c\u4e0d\u540c\u5b9e\u4f53\u4e4b\u95f4\u7684\u5173\u7cfb\u7531\u5916\u952e\u7684\u5b58\u5728\u6765\u8868\u793a\u3002\u5728\u56fe 8.3 \u4e2d\uff0cCountry \u548c City \u901a\u8fc7 City \u8868\u4e0a\u7684 CountryId \u5916\u952e\u4ee5\u4e00\u5bf9\u591a\u7684\u5173\u7cfb\u5173\u8054\u3002<\/p>\n

<\/p>\n

\u56fe 8.3 \u56fd\u5bb6\/\u5730\u533a\u548c\u57ce\u5e02\u4e4b\u95f4\u5b58\u5728\u4e00\u5bf9\u591a\u5173\u7cfb\uff0c\u4e00\u4e2a\u56fd\u5bb6\u53ef\u4ee5\u6709\u591a\u4e2a\u57ce\u5e02\u3002<\/p>\n

\u6309\u7167\u60ef\u4f8b\uff0cEF Core \u6a21\u578b\u4e2d\u7684\u5173\u7cfb\u7531\u5bfc\u822a\u5c5e\u6027\u8868\u793a\u3002\u8fd9\u4e9b\u662f\u7c7b\u4e2d\u7684\u5c5e\u6027\uff0c\u4e0d\u80fd\u6620\u5c04\u5230\u57fa\u5143\u6216\u6807\u91cf\u503c\uff0c\u4f8b\u5982\u5b57\u7b26\u4e32\u3001\u5e03\u5c14\u503c\u3001\u6574\u6570\u6216\u65e5\u671f\u65f6\u95f4\u7c7b\u578b\u3002\u60a8\u73b0\u6709\u7684 City \u7c7b\uff08\u8bf7\u53c2\u9605\u4e0b\u4e00\u4e2a\u6e05\u5355\uff09\u5df2\u7ecf\u5177\u6709\u4e00\u4e2a\u7b26\u5408\u5bfc\u822a\u5c5e\u6027\u63cf\u8ff0\u7684 Country \u5c5e\u6027\u3002<\/p>\n

\u6e05\u5355 8.1 \u5177\u6709 Country \u5bfc\u822a\u5c5e\u6027\u7684 City \u7c7b<\/p>\n

public class City\n{\n    public int Id { get; set; }\n    public string Name { get; set; }\n    public Country Country { get; set; }    \u2776\n}<\/code><\/pre>\n
\u2776 Country \u662f\u4e00\u4e2a\u5bfc\u822a\u5c5e\u6027\u3002<\/p>\n
\u8fd9\u5c31\u662f EF Core \u63a8\u65ad Country \u548c City \u5b9e\u4f53\u4e4b\u95f4\u7684\u4e00\u5bf9\u591a\u5173\u7cfb\u6240\u9700\u7684\u5168\u90e8\u5185\u5bb9\uff0c\u5176\u4e2d Country \u662f\u5173\u7cfb\u4e2d\u7684\u4e3b\u4f53\uff0cCity \u662f\u4f9d\u8d56\u9879\u3002\u5728\u6b64\u793a\u4f8b\u4e2d\uff0cCountry \u5c5e\u6027\u79f0\u4e3a\u5f15\u7528\u5bfc\u822a\u5c5e\u6027\uff0c\u8be5\u5c5e\u6027\u7684\u91cd\u6570\uff08\u5173\u7cfb\u4e00\u7aef\u7684\u6f5c\u5728\u9879\u6570\uff09\u4e3a 0 \u6216 1\u3002\u66f4\u5e38\u89c1\u7684\u662f\uff0cEF Core \u5173\u7cfb\u662f\u5b8c\u5168\u5b9a\u4e49\u7684\uff0c\u5177\u6709\u8868\u793a\u5173\u7cfb\u6bcf\u4e00\u7aef\u7684\u5c5e\u6027\u548c\u4e00\u4e2a\u8868\u793a\u5916\u952e\u503c\u7684\u5c5e\u6027\u3002\u5728\u5217\u8868 8.2 \u4e2d\uff0c\u60a8\u5c06\u4e00\u4e2a\u8868\u793a CountryId \u5916\u952e\u7684\u5c5e\u6027\u6dfb\u52a0\u5230 City \u7c7b\u4e2d\uff0c\u5e76\u5411 Country \u7c7b\u6dfb\u52a0\u4e00\u4e2a\u96c6\u5408\u5bfc\u822a\u5c5e\u6027\uff0c\u8be5\u7c7b\u8868\u793a\u53ef\u80fd\u5c5e\u4e8e\u5355\u4e2a\u56fd\u5bb6\/\u5730\u533a\u7684\u6240\u6709\u57ce\u5e02\u3002\u4f5c\u4e3a\u6700\u4f73\u5b9e\u8df5\uff0c\u60a8\u5e94\u8be5\u59cb\u7ec8\u5c06\u96c6\u5408\u5bfc\u822a\u5c5e\u6027\u4f5c\u4e3a\u5176\u58f0\u660e\u7684\u4e00\u90e8\u5206\u8fdb\u884c\u5b9e\u4f8b\u5316\uff0c\u8fd9\u6837\u5c31\u53ef\u4ee5\u907f\u514d\u5728\u4ee3\u7801\u4e2d\u8bbf\u95ee\u5b83\u4eec\u65f6\u5fc5\u987b\u6d4b\u8bd5 null\u3002<\/p>\n
\u6e05\u5355 8.2 Country \u548c City \u4e4b\u95f4\u5b8c\u5168\u5b9a\u4e49\u7684\u4e00\u5bf9\u591a\u5173\u7cfb<\/p>\n
public class City\n{\n    public int Id { get; set; }\n    public string Name { get; set; }\n    public int CountryId { get; set; }                          \u2776\n    public Country Country { get; set; }                        \u2777\n}\n\npublic class Country\n{\n    public int Id { get; set; }\n    public string CountryName { get; set; }\n    public string CountryCode { get; set; }\n    public List<City> Cities { get; set; } = new List<City>();  \u2778\n}<\/code><\/pre>\n
\u2776 \u5916\u952e\u5c5e\u6027
\n\u2777 \u5f15\u7528\u5bfc\u822a\u5c5e\u6027\uff0c\u8868\u793a\u57ce\u5e02\u6240\u5c5e\u7684\u56fd\u5bb6\/\u5730\u533a
\n\u2778 \u96c6\u5408\u5bfc\u822a\u5c5e\u6027\uff0c\u8868\u793a\u53ef\u4ee5\u5c5e\u4e8e\u4e00\u4e2a\u56fd\u5bb6\/\u5730\u533a\u7684\u8bb8\u591a\u57ce\u5e02\uff0c\u5b9e\u4f8b\u5316\u4ee5\u786e\u4fdd\u5b83\u6c38\u8fdc\u4e0d\u4f1a\u4e3a null<\/p>\n
\u9762\u5411\u5bf9\u8c61\u7684\u7eaf\u7cb9\u4e3b\u4e49\u8005\u901a\u5e38\u4e0d\u70ed\u8877\u4e8e\u5728\u9886\u57df\u7c7b\u4e2d\u5305\u542b\u5916\u952e\u5c5e\u6027\u7684\u60f3\u6cd5\uff0c\u56e0\u4e3a\u4ed6\u4eec\u8ba4\u4e3a\u8fd9\u662f\u5173\u7cfb\u6570\u636e\u5e93\u4e16\u754c\u201c\u6e17\u5165\u201d\u9886\u57df\u7684\u4e00\u4e2a\u4f8b\u5b50\u3002\u5982\u679c\u7701\u7565\u5916\u952e\u5c5e\u6027\uff0cEF Core \u5c06\u521b\u5efa\u4e00\u4e2a\u5f71\u5b50\u5916\u952e\u5c5e\u6027 \uff08http:\/\/mng.bz\/Xawa<\/a>\uff09 \u4f5c\u4e3a\u5176\u6982\u5ff5\u6a21\u578b\u7684\u4e00\u90e8\u5206\u3002<\/p>\n
\u6309\u7167\u7ea6\u5b9a\uff0c\u540d\u4e3a Id \u6216 Id \u7684\u5c5e\u6027\u88ab\u89c6\u4e3a\u4e3b\u952e\u503c\uff0cEF Core \u4f1a\u5c06\u5176\u6620\u5c04\u5230 IDENTITY \u5217\u3002\u4e24\u4e2a\u57df\u7c7b\u90fd\u6709\u4e00\u4e2a Id \u5c5e\u6027\uff0c\u4f46 EF Core \u8fd8\u4f1a\u5728 city \u7c7b\u4e2d\u770b\u5230 CityId \u6216\u5728 country \u7c7b\u4e2d\u770b\u5230 CountryId \u4f5c\u4e3a\u8868\u793a\u4e3b\u952e\u3002\u5728\u6211\u4eec\u7684\u793a\u4f8b\u4e2d\uff0c\u5916\u952e\u5c5e\u6027\u5e94\u4f7f\u7528\u5f15\u7528\u5bfc\u822a\u5c5e\u6027\u7684\u540d\u79f0\uff0c\u540e\u8ddf Id\u2014CountryId\u3002<\/p>\n
\u60a8\u5c1a\u672a\u5728\u6a21\u578b\u4e2d\u521b\u5efa\u4e00\u4e2a\u7c7b\uff0c\u8be5\u7c7b\u8868\u793a\u5ea6\u5047\u8005\u53ef\u4ee5\u79df\u7528\u7684\u623f\u4ea7\u3002\u56e0\u6b64\uff0c\u4f7f\u7528\u4e0a\u9762\u7684\u4fe1\u606f\u5728\u57ce\u5e02\u548c\u5c5e\u6027\u4e4b\u95f4\u521b\u5efa\u4e00\u5bf9\u591a\u7684\u5173\u7cfb\uff0c\u4e0b\u9762\u7684\u6e05\u5355\u663e\u793a\u4e86\u5e94\u8be5\u6dfb\u52a0\u5230 Models \u6587\u4ef6\u5939\u7684 Property \u7c7b\u3002<\/p>\n
\u793a\u4f8b 8.3 Property \u7c7b<\/p>\n
public class Property\n{\n    public int Id { get; set; }                  \u2776\n    public string Name { get; set; }\n    public string Address { get; set; }\n    public int CityId { get; set; }              \u2777\n    public City City { get; set; }               \u2777\n    public int MaxNumberOfGuests { get; set; }\n    public decimal DayRate { get; set; }\n    public bool SmokingPermitted { get; set; }\n    public DateTime AvailableFrom { get; set; }\n}<\/code><\/pre>\n
\u2776 \u4e3b\u952e\u5c5e\u6027
\n\u2777 \u5916\u952e\u548c\u5f15\u7528\u5bfc\u822a\u5c5e\u6027<\/p>\n
\u60a8\u8fd8\u9700\u8981\u4fee\u6539 City \u7c7b\uff0c\u4ee5\u5305\u542b\u4e00\u4e2a\u96c6\u5408\u5bfc\u822a\u5c5e\u6027\uff0c\u8be5\u5c5e\u6027\u8868\u793a\u5c5e\u4e8e\u57ce\u5e02\u7684\u5c5e\u6027\uff0c\u5728\u4e0b\u9762\u7684\u6e05\u5355\u4e2d\u4ee5\u7c97\u4f53\u663e\u793a\u3002<\/p>\n
\u6e05\u5355 8.4 \u66f4\u65b0 City \u7c7b\u4ee5\u5305\u542b Properties \u7684\u96c6\u5408<\/p>\n
public class City\n{\n    public int Id { get; set; }\n    public string Name { get; set; }\n    public int CountryId { get; set; }\n    public Country Country { get; set; }\n    public List<Property> Properties { get; set; } = new List<Property>();\n}<\/code><\/pre>\n
\u73b0\u5728\uff0c\u6a21\u578b\u5df2\u914d\u7f6e\u597d\uff0c\u4ee5\u4fbf EF Core \u80fd\u591f\u8bc6\u522b\u5176\u5173\u7cfb\uff0c\u4f60\u53ef\u4ee5\u5f00\u59cb\u4f7f\u7528 EF Core\u3002<\/p>\n
8.1.4 \u5b89\u88c5 Entity Framework Core<\/h3>\n
\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0cEF Core \u4e0d\u5305\u542b\u5728 Web \u5e94\u7528\u7a0b\u5e8f\u9879\u76ee\u4e2d\u3002\u9700\u8981\u5c06\u5176\u4f5c\u4e3a NuGet \u7684\u9644\u52a0\u5305\u8fdb\u884c\u5b89\u88c5\u3002\u5b89\u88c5\u5305\u7684\u6700\u7b80\u5355\u65b9\u6cd5\uff08\u4e0d\u4f9d\u8d56\u4e8e\u6240\u4f7f\u7528\u7684 IDE\uff09\u662f\u5411\u9879\u76ee\u6587\u4ef6\u6dfb\u52a0\u65b0\u7684\u5305\u5f15\u7528\uff1a\u5e94\u7528\u7a0b\u5e8f\u6587\u4ef6\u5939\u6839\u76ee\u5f55\u4e2d\u7684 CityBreaks.csproj \u6587\u4ef6\u3002\u9879\u76ee\u6587\u4ef6\u5728\u8d44\u6e90\u7ba1\u7406\u5668\u4e2d\u53ef\u89c1\uff0c\u5982\u679c\u60a8\u4f7f\u7528\u7684\u662f VS Code\uff0c\u5219\u53ef\u4ee5\u8f7b\u677e\u8bbf\u95ee\u3002\u5b83\u5728 Visual Studio \u89e3\u51b3\u65b9\u6848\u8d44\u6e90\u7ba1\u7406\u5668\u4e2d\u4e0d\u53ef\u89c1\u3002\u60a8\u9700\u8981\u53f3\u952e\u5355\u51fb\u9879\u76ee\u540d\u79f0\uff0c\u7136\u540e\u4ece\u51fa\u73b0\u7684\u4e0a\u4e0b\u6587\u83dc\u5355\u4e2d\u9009\u62e9 Edit Project File\u3002\u6253\u5f00\u6587\u4ef6\u540e\uff0c\u5c06\u65b0\u7684 PackageReference \u6761\u76ee\u6dfb\u52a0\u5230\u73b0\u6709 ItemGroup \u4e2d\uff0c\u6216\u521b\u5efa\u65b0\u7684 ItemGroup \u8282\u70b9\uff1a<\/p>\n
<ItemGroup>\n   <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" \n    \u27a5 Version="6.0.0" \/>\n<\/ItemGroup><\/code><\/pre>\n
Visual Studio \u7528\u6237\u5e94\u8be5\u6ce8\u610f\u5230\uff0c\u5f53\u4f60\u4ee5\u8fd9\u79cd\u65b9\u5f0f\u6dfb\u52a0\u5305\u65f6\uff0cVS \u4f1a\u81ea\u52a8\u8fd0\u884c restore \u547d\u4ee4\u5e76\u4ece NuGet \u83b7\u53d6\u6240\u9700\u7684\u5e93\u3002\u4f7f\u7528 VS Code\uff0c\u60a8\u9700\u8981\u4ece\u7ec8\u7aef\u81ea\u884c\u6267\u884c dotnet restore \u547d\u4ee4\u3002C# \u6269\u5c55\u5e94\u63d0\u793a\u60a8\u6267\u884c\u6b64\u4f5c\u3002<\/p>\n
\u6216\u8005\uff0c\u53ef\u4ee5\u4f7f\u7528 dotnet add \u547d\u4ee4\u5728 VS Code \u4e2d\u6dfb\u52a0\u5305\u3002\u547d\u4ee4\u4e3a\uff1a<\/p>\n
dotnet add package Microsoft.EntityFrameworkCore.Sqlite<\/code><\/pre>\n
\u6267\u884c\u8be5\u547d\u4ee4\u540e\uff0cVS Code \u5c06\u81ea\u52a8\u6062\u590d\u6240\u6709\u5305\u3002<\/p>\n
Visual Studio \u7528\u6237\u5177\u6709\u7528\u4e8e\u7ba1\u7406\u5305\u7684\u5185\u7f6e\u5de5\u5177\u3002\u8f6c\u5230 NuGet \u5305\u7ba1\u7406\u5668>\u5de5\u5177\u201c\uff0c\u7136\u540e\u4ece\u90a3\u91cc\uff0c\u60a8\u53ef\u4ee5\u9009\u62e9 Manage NuGet Packages for Solution\u3002\u8fd9\u5c06\u6253\u5f00\u4e00\u4e2a\u4eea\u8868\u677f UI\uff0c\u5141\u8bb8\u60a8\u7ba1\u7406\u4ee5\u524d\u5b89\u88c5\u7684\u8f6f\u4ef6\u5305\u4ee5\u53ca\u641c\u7d22\u548c\u5b89\u88c5\u5176\u4ed6\u8f6f\u4ef6\u5305\u3002\u6216\u8005\uff0c\u60a8\u53ef\u4ee5\u8c03\u7528 Package Manager \u63a7\u5236\u53f0 \uff08PMC\uff09 \u5e76\u6267\u884c\u7528\u4e8e\u7ba1\u7406\u5305\u7684\u547d\u4ee4\u3002\u8981\u6dfb\u52a0\u8f6f\u4ef6\u5305\uff0c\u8bf7\u4f7f\u7528 install-package \u547d\u4ee4\uff1a<\/p>\n
install-package Microsoft.EntityFrameworkCore.Sqlite<\/code><\/pre>\n
\u540c\u6837\uff0cVS \u5c06\u5728\u89e3\u51b3\u5305\u540e\u81ea\u52a8\u8fd8\u539f\u5305\u3002<\/p>\n
8.1.5 \u521b\u5efa\u4e0a\u4e0b\u6587<\/h3>\n
\u5728\u4ee3\u7801\u4e2d\u4f7f\u7528 EF Core \u7684\u5165\u53e3\u70b9\u662f\u4e0a\u4e0b\u6587\uff0c\u5373\u6d3e\u751f\u81ea DbContext \u7684\u5bf9\u8c61\u3002\u5b83\u8868\u793a\u4e0e\u6570\u636e\u5e93\u7684\u4f1a\u8bdd\uff0c\u5e76\u63d0\u4f9b\u7528\u4e8e\u4e0e\u6570\u636e\u5e93\u901a\u4fe1\u4ee5\u6267\u884c\u6570\u636e\u4f5c\uff08\u5982\u67e5\u8be2\u548c\u6570\u636e\u6301\u4e45\u6027\uff09\u7684 API\u3002\u5b83\u8fd8\u652f\u6301\u66f4\u9ad8\u7ea7\u7684\u529f\u80fd\uff0c\u4f8b\u5982\u6a21\u578b\u6784\u5efa\u548c\u6570\u636e\u6620\u5c04\uff08\u6211\u4eec\u5c06\u5728\u540e\u9762\u4ecb\u7ecd\uff09\uff0c\u4ee5\u53ca\u4e8b\u52a1\u7ba1\u7406\u3001\u5bf9\u8c61\u7f13\u5b58\u548c\u66f4\u6539\u8ddf\u8e2a\uff0c\u8fd9\u4e9b\u529f\u80fd\u5728\u672c\u4e66\u4e2d\u4e0d\u6d89\u53ca\u3002<\/p>\n
\u5c06\u5de5\u4f5c\u4e0a\u4e0b\u6587\u4ea4\u4ed8\u7ed9\u5e94\u7528\u7a0b\u5e8f\u6240\u9700\u7684\u6b65\u9aa4\u662f<\/p>\n
    \n
  1. \u521b\u5efa\u4ece DbContext \u6d3e\u751f\u7684\u7c7b\u3002<\/li>\n
  2. \u63d0\u4f9b\u8fde\u63a5\u5b57\u7b26\u4e32\u3002<\/li>\n
  3. \u5411\u670d\u52a1\u5bb9\u5668\u6ce8\u518c\u4e0a\u4e0b\u6587\u3002<\/li>\n<\/ol>\n
    \u4ece\u6b65\u9aa4 1 \u5f00\u59cb\uff0c\u5411\u9879\u76ee\u4e2d\u6dfb\u52a0\u4e00\u4e2a\u540d\u4e3a Data \u7684\u65b0\u6587\u4ef6\u5939\uff0c\u5e76\u5728\u8be5\u6587\u4ef6\u5939\u4e2d\u6dfb\u52a0\u4e00\u4e2a\u540d\u4e3a CityBreaksContext.cs \u7684\u65b0\u7c7b\u6587\u4ef6\uff0c\u5176\u4e2d\u5305\u542b\u4ee5\u4e0b\u4ee3\u7801\u3002<\/p>\n
    \u6e05\u5355 8.5 CityBreaksContext<\/p>\n
    using Microsoft.EntityFrameworkCore;\n namespace CityBreaks.Data\n{\n    public class CityBreaksContext : DbContext\n    {\n        public CityBreaksContext(DbContextOptions options) : base(options)\n        {\n        }    \n    }\n}<\/code><\/pre>\n
    \u8be5\u7c7b\u5177\u6709\u4e00\u4e2a\u5c06 DbContextOptions \u5bf9\u8c61\u4f5c\u4e3a\u53c2\u6570\u7684\u6784\u9020\u51fd\u6570\u3002\u5728\u5c06\u4e0a\u4e0b\u6587\u6ce8\u518c\u4e3a\u670d\u52a1\u65f6\uff0c\u60a8\u5c06\u914d\u7f6e\u6b64\u5bf9\u8c61\uff0c\u5e76\u63d0\u4f9b\u8fde\u63a5\u5b57\u7b26\u4e32\u3002\u9996\u5148\uff0c\u60a8\u9700\u8981\u5411\u5e94\u7528\u7a0b\u5e8f\u6dfb\u52a0\u8fde\u63a5\u5b57\u7b26\u4e32\u3002\u4e3a\u6b64\uff0c\u60a8\u5c06\u4f7f\u7528\u4e3b\u914d\u7f6e\u6587\u4ef6\u3002\u5982\u679c\u60a8\u8fd8\u8bb0\u5f97\u7b2c 2 \u7ae0\uff0c\u8fd9\u662f appSettings.json \u6587\u4ef6\u3002\u60a8\u5c06\u6dfb\u52a0\u4e00\u4e2a\u540d\u4e3a ConnectionStrings \u7684\u5c5e\u6027\u3002\u6b64\u5c5e\u6027\u6216\u90e8\u5206\u7684\u547d\u540d\u975e\u5e38\u91cd\u8981\uff0c\u56e0\u4e3a\u5b83\u662f\u914d\u7f6e API \u67e5\u627e\u8fde\u63a5\u5b57\u7b26\u4e32\u6240\u4f9d\u8d56\u7684\u7ea6\u5b9a\u3002\u7136\u540e\uff0c\u60a8\u5c06\u63d0\u4f9b\u8fde\u63a5\u5b57\u7b26\u4e32\u7684\u540d\u79f0\u53ca\u5176\u503c\u3002<\/p>\n
    \u6e05\u5355 8.6 \u5411 appSettings.json \u6dfb\u52a0\u8fde\u63a5\u5b57\u7b26\u4e32<\/p>\n
    {\n  "Logging": {\n    "LogLevel": {\n      "Default": "Information",\n      "Microsoft": "Warning",\n      "Microsoft.Hosting.Lifetime": "Information"\n    }\n  },\n  "AllowedHosts": "*",\n  "ConnectionStrings": {    \n    "CityBreaksContext": "Data source=Data\/CityBreaks.db"   \u2776\n  }    \n}<\/code><\/pre>\n
    \u2776 \u8fde\u63a5\u5b57\u7b26\u4e32\u90e8\u5206\u548c\u5b9e\u9645\u8fde\u63a5\u5b57\u7b26\u4e32<\/p>\n
    SQLite \u8fde\u63a5\u5b57\u7b26\u4e32\u5f88\u597d\uff0c\u5f88\u7b80\u5355\uff0c\u8868\u793a\u6570\u636e\u5e93\u6587\u4ef6\u7684\u8def\u5f84\u3002\u5728\u60a8\u7684\u5e94\u7528\u7a0b\u5e8f\u4e2d\uff0c\u60a8\u5c06\u6570\u636e\u5e93\u6587\u4ef6\u653e\u5728 Data \u6587\u4ef6\u5939\u4e2d\uff0c\u4e0e\u4e0a\u4e0b\u6587\u5e76\u6392\u3002\u7a0d\u540e\u8fd0\u884c\u7b2c\u4e00\u6b21\u8fc1\u79fb\u65f6\uff0cEF Core \u5c06\u521b\u5efa\u8be5\u6587\u4ef6\u3002<\/p>\n
    \u6700\u540e\u4e00\u6b65\u662f\u5411\u670d\u52a1\u5bb9\u5668\u6ce8\u518c\u4e0a\u4e0b\u6587\u3002\u6b63\u5982\u60a8\u4ece\u4e0a\u4e00\u7ae0\u4e2d\u5b66\u5230\u7684\u90a3\u6837\uff0c\u60a8\u53ef\u4ee5\u5728 Program.cs \u6587\u4ef6\u4e2d\u6267\u884c\u6b64\u4f5c\u3002\u5728\u6dfb\u52a0\u4ee5\u4e0b\u4ee3\u7801\u4e4b\u524d\uff0c\u60a8\u9700\u8981\u6dfb\u52a0\u4e00\u4e9b using \u6307\u4ee4\u4ee5\u5f15\u5165 Microsoft.EntityFrameworkCore \u548c CityBreaks.Data\u3002<\/p>\n
    \u6e05\u5355 8.7 \u914d\u7f6e CityBreaksContext<\/p>\n
    builder.Services.AddDbContext<CityBreaksContext>(options =>\n{\n    options.UseSqlite(builder.Configuration.GetConnectionString\n    \u27a5 ("CityBreaksContext"));\n});<\/code><\/pre>\n
    GetConnectionString \u65b9\u6cd5\u5728 appSettings.json \u7684 ConnectionStrings \u90e8\u5206\u4e2d\u627e\u5230\u6307\u5b9a\u7684\u8fde\u63a5\u5b57\u7b26\u4e32\uff0c\u800c UseSqlite \u65b9\u6cd5\u5219\u8bbe\u7f6e\u6b63\u786e\u7684\u6570\u636e\u5e93\u63d0\u4f9b\u7a0b\u5e8f\u4f9b EF Core \u4f7f\u7528\u3002<\/p>\n
    \u60a8\u62e5\u6709\u4e0a\u4e0b\u6587\u5e76\u5c06\u5176\u6ce8\u518c\u4e3a\u670d\u52a1\u3002\u76ee\u524d\uff0c\u5b83\u51e0\u4e4e\u6ca1\u7528;\u8fd9\u5c31\u50cf\u6709\u4e00\u4e2a\u7a7a\u7684\u6570\u636e\u5e93\u3002\u60a8\u5c06\u9700\u8981\u4e00\u4e9b\u5728\u4e0a\u4e0b\u6587\u4e2d\u7531 DbSet<TEntity><\/code> \u5c5e\u6027\u8868\u793a\u7684\u6570\u636e\u5e93\u8868\uff0c\u5176\u4e2d TEntity \u662f\u60a8\u5e0c\u671b\u8868\u8868\u793a\u7684\u5b9e\u4f53\u3002\u56fe 8.4 \u8bf4\u660e\u4e86\u5b9e\u4f53\u3001DbSet\u548c\u6570\u636e\u5e93\u4e4b\u95f4\u7684\u5173\u7cfb\u3002<\/p>\n
    <\/p>\n
    \u56fe 8.4 \u6bcf\u4e2a\u5b9e\u4f53\u90fd\u7531\u4e00\u4e2a DbSet \u8868\u793a\uff0c\u8be5 DbSet \u6620\u5c04\u5230\u6570\u636e\u5e93\u4e2d\u7684\u8868\u3002<\/p>\n
    8.1.6 \u6dfb\u52a0 DbSet<\/h3>\n
    \u9996\u5148\uff0c\u60a8\u5c06 DbSet \u6dfb\u52a0\u5230\u8981\u6620\u5c04\u5230\u6570\u636e\u5e93\u8868\u7684\u6bcf\u4e2a\u5b9e\u4f53\u7684\u4e0a\u4e0b\u6587\u4e2d\u3002\u6309\u7167\u7ea6\u5b9a\uff0c\u8be5\u8868\u5c06\u91c7\u7528 DbSet \u5c5e\u6027\u7684\u540d\u79f0\u3002\u4e0b\u4e00\u4e2a\u6e05\u5355\u663e\u793a\u4e86\u5230\u76ee\u524d\u4e3a\u6b62\u60a8\u5728\u6a21\u578b\u4e2d\u521b\u5efa\u7684\u4e09\u4e2a\u7c7b\uff0c\u6bcf\u4e2a\u7c7b\u90fd\u8868\u793a\u4e3a DbSet<TEntity><\/code>\u3002<\/p>\n
    \u5217\u8868 8.8 \u6620\u5c04\u5230\u6570\u636e\u5e93\u4e2d\u7684 Table \u7684 DbSet \u5c5e\u6027<\/p>\n
    public class CityBreaksContext : DbContext\n{\n    public CityBreaksContext(DbContextOptions options) : base(options)\n    {\n\n    }\n    public DbSet<City> Cities { get; set; }\n    public DbSet<Country> Countries { get; set; }\n    public DbSet<Property> Properties { get; set; }\n}<\/code><\/pre>\n
    8.1.7 \u914d\u7f6e\u6a21\u578b<\/h3>\n
    \u5982\u679c\u8981\u5728\u6b64\u9636\u6bb5\u521b\u5efa\u8fc1\u79fb\uff0c\u5b83\u5c06\u751f\u6210\u4e00\u4e2a\u5305\u542b\u4e09\u4e2a\u8868\u7684\u6570\u636e\u5e93\uff0c\u6bcf\u4e2a DbSet \u4e00\u4e2a\u8868\uff0c\u5e76\u4e14\u5b83\u5c06\u4f7f\u7528\u7ea6\u5b9a\u6839\u636e DbSet \u7c7b\u578b\u53c2\u6570\u8868\u793a\u7684\u6bcf\u79cd\u7c7b\u578b\u7684\u5c5e\u6027\u521b\u5efa\u5217\u3002\u5728\u5927\u591a\u6570\u5b9e\u9645\u5e94\u7528\u7a0b\u5e8f\u4e2d\uff0c\u9ed8\u8ba4\u7ea6\u5b9a\u5bf9\u4e8e\u5927\u591a\u6570\u6a21\u578b\u90fd\u662f\u53ef\u4ee5\u63a5\u53d7\u7684\uff0c\u5c24\u5176\u662f\u5728\u60a8\u4ece\u5934\u5f00\u59cb\u65f6\u3002\u5bf9\u4e8e\u7ea6\u5b9a\u4e0d\u9002\u7528\u6216 EF Core \u9700\u8981\u5e2e\u52a9\u4e86\u89e3\u4f60\u7684\u610f\u56fe\u7684\u60c5\u51b5\uff0cEF Core \u63d0\u4f9b\u4e86\u5141\u8bb8\u4f60\u66ff\u4ee3\u7ea6\u5b9a\u7684\u914d\u7f6e API\u3002<\/p>\n
    \u914d\u7f6e\u9762\u5411\u4e09\u4e2a\u7ea7\u522b\uff1a\u6a21\u578b\u3001\u7c7b\u578b\u548c\u5c5e\u6027\u3002\u60a8\u53ef\u4ee5\u5728\u6a21\u578b\u7ea7\u522b\u914d\u7f6e EF Core \u7528\u4e8e\u5bf9\u8c61\u7684\u67b6\u6784\u3002\u7c7b\u578b\u914d\u7f6e\u9009\u9879\u4f7f\u60a8\u80fd\u591f\u914d\u7f6e\u7c7b\u578b\u6620\u5c04\u5230\u7684\u8868\u540d\u79f0\uff0c\u6216\u8005\u5e94\u5982\u4f55\u6307\u5b9a\u7c7b\u578b\u4e4b\u95f4\u7684\u5173\u7cfb\u3002\u5c5e\u6027\u914d\u7f6e\u63d0\u4f9b\u4e86\u5e7f\u6cdb\u7684\u9009\u9879\uff0c\u7528\u4e8e\u7ba1\u7406\u5404\u4e2a\u5c5e\u6027\u6620\u5c04\u5230\u5217\u7684\u65b9\u5f0f\uff0c\u5305\u62ec\u5176\u540d\u79f0\u3001\u6570\u636e\u7c7b\u578b\u3001\u9ed8\u8ba4\u503c\u7b49\u3002<\/p>\n
    \u53ef\u4ee5\u901a\u8fc7\u4e24\u79cd\u65b9\u5f0f\u5e94\u7528\u914d\u7f6e\uff1a\u4f7f\u7528\u7279\u6027\u4fee\u9970\u7c7b\u548c\u5c5e\u6027\uff0c\u6216\u8005\u4f7f\u7528\u7531\u53ef\u94fe\u63a5\u5728\u4e00\u8d77\u7684\u6269\u5c55\u65b9\u6cd5\u96c6\u5408\u7ec4\u6210\u7684 Fluent API\u3002\u5c5e\u6027\u4ec5\u63d0\u4f9b\u914d\u7f6e\u9009\u9879\u7684\u5b50\u96c6\u3002\u56e0\u6b64\uff0c\u5bf9\u4e8e\u4efb\u4f55\u76f8\u5f53\u590d\u6742\u7684\u6a21\u578b\uff0c\u4f60\u90fd\u53ef\u80fd\u9700\u8981\u4f9d\u8d56 Fluent API \u8fdb\u884c\u67d0\u4e9b\u914d\u7f6e\u3002\u56e0\u6b64\uff0c\u5bf9\u6240\u6709\u914d\u7f6e\u4f7f\u7528 Fluent API \u662f\u6709\u610f\u4e49\u7684\uff0c\u8fd9\u6837\u53ef\u4ee5\u4fdd\u6301\u914d\u7f6e\u4ee3\u7801\u7684\u4e00\u81f4\u6027\uff0c\u4ece\u800c\u66f4\u5bb9\u6613\u63a8\u7406\uff0c\u5e76\u4e14\u96c6\u4e2d\u5728\u4e00\u4e2a\u5730\u65b9\u3002<\/p>\n
    \u90a3\u4e48\uff0c\u60a8\u5e94\u8be5\u5c06 Fluent API \u914d\u7f6e\u4ee3\u7801\u653e\u5728\u54ea\u91cc\u5462\uff1f\u60a8\u6709\u4e24\u4e2a\u9009\u9879\uff1a\u53ef\u4ee5\u5728\u81ea\u5df1\u7684\u4e0a\u4e0b\u6587\u7c7b\u4e2d\u91cd\u5199 DbContext OnModelCreating \u65b9\u6cd5\u5e76\u5c06\u914d\u7f6e\u4ee3\u7801\u653e\u5728\u8be5\u4e0a\u4e0b\u6587\u4e2d\uff0c\u4e5f\u53ef\u4ee5\u5c06\u914d\u7f6e\u4ee3\u7801\u653e\u5728\u6bcf\u4e2a\u5b9e\u4f53\u7684\u5355\u72ec\u7c7b\u4e2d\uff0c\u7136\u540e\u5728 OnModelCreating \u65b9\u6cd5\u4e2d\u5f15\u7528\u8fd9\u4e9b\u7c7b\u3002\u60a8\u5c06\u91c7\u7528\u540e\u4e00\u79cd\u65b9\u6cd5\uff0c\u56e0\u4e3a\u5b83\u662f\u7ba1\u7406\u5e94\u7528\u7a0b\u5e8f\u8fd9\u4e00\u65b9\u9762\u7684\u63a8\u8350\u65b9\u6cd5\u3002<\/p>\n
    \u914d\u7f6e\u7c7b\u6d3e\u751f\u81ea IEntityTypeConfiguration<TEntity><\/code>\uff0c\u5b83\u5b9e\u73b0\u4e00\u79cd\u65b9\u6cd5 Configure\uff0c\u8be5\u65b9\u6cd5\u5c06 EntityTypeBuilder<TEntity><\/code> \u4f5c\u4e3a\u53c2\u6570\u3002\u60a8\u5c06\u5728\u6b64\u5904\u653e\u7f6e\u914d\u7f6e\u4ee3\u7801\u3002<\/p>\n
    \u9996\u5148\u5728 Data \u6587\u4ef6\u5939\u4e2d\u521b\u5efa\u4e00\u4e2a\u65b0\u6587\u4ef6\u5939\uff0c\u5c06\u5176\u547d\u540d\u4e3a Configurations\u3002\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u7801\u5c06\u540d\u4e3a CountryConfiguration \u7684 C# \u7c7b\u6587\u4ef6\u6dfb\u52a0\u5230\u65b0\u6587\u4ef6\u5939\u4e2d\u3002<\/p>\n
    \u5217\u8868 8.9 CountryConfiguration \u7c7b<\/p>\n
    using CityBreaks.Models;\nusing Microsoft.EntityFrameworkCore;\nusing Microsoft.EntityFrameworkCore.Metadata.Builders;\n\nnamespace CityBreaks.Data.Configuration;\npublic class CountryConfiguration : IEntityTypeConfiguration<Country>   \u2776\n{\n    public void Configure(EntityTypeBuilder<Country> builder)           \u2777\n    {\n        builder.Property(x => x.CountryName)\n            .HasMaxLength(50);                                          \u2778\n        builder.Property(x => x.CountryCode)\n            .HasColumnName("ISO 3166 code")                             \u2779\n            .HasMaxLength(2);                                           \u2779\n    }\n}<\/code><\/pre>\n
    \u2776 \u8be5\u7c7b\u5b9e\u73b0 IEntityTypeConfiguration\u3002
    \n\u2777 \u6839\u636e\u63a5\u53e3\u7684\u8981\u6c42\u5b9e\u73b0 Configure \u65b9\u6cd5\u3002
    \n\u2778 \u4f7f\u7528 HasMaxLength \u65b9\u6cd5\u7ea6\u675f CountryName \u5c5e\u6027\u7684\u6587\u672c\u5b57\u6bb5\u7684\u957f\u5ea6\u3002
    \n\u2779 \u5c06 CountryCode \u5c5e\u6027\u6620\u5c04\u5230\u540d\u4e3a\u201cISO 3166 Code\u201d\u7684\u5217\u5e76\u9650\u5236\u5176\u5927\u5c0f\u3002<\/p>\n
    \u5b57\u7b26\u4e32\u5c5e\u6027\u901a\u5e38\u6620\u5c04\u5230 SQL Server \u4e2d\u7684 nvarchar\uff08max\uff09 \u6570\u636e\u7c7b\u578b\u3002\u60a8\u5df2\u4f7f\u7528 HasMaxLength \u65b9\u6cd5\u5bf9\u652f\u6301\u57fa\u4e8e\u6587\u672c\u7684\u5217\u7684\u6570\u636e\u5e93\u4e2d\u57fa\u4e8e\u6587\u672c\u7684\u5217\u7684\u5927\u5c0f\u5e94\u7528\u9650\u5236\u3002SQLite \u4e0d\u652f\u6301\u6b64\u65b9\u6cd5\uff0c\u56e0\u6b64\u9664\u975e\u60a8\u4f7f\u7528\u7684\u662f SQL Server\uff0c\u5426\u5219\u6b64\u914d\u7f6e\u5c06\u4e0d\u8d77\u4f5c\u7528\u3002\u4e0d\u8fc7\uff0cHasColumnName \u65b9\u6cd5\u5c06\u9002\u7528\u4e8e\u4efb\u4f55\u6570\u636e\u5e93\uff0c\u5e76\u5c06 CountryCode \u5c5e\u6027\u6620\u5c04\u5230\u201cISO 3166 \u4ee3\u7801\u201d\u5217\u3002\u5728\u914d\u7f6e CountryCode \u5c5e\u6027\u65f6\uff0c\u60a8\u53ef\u4ee5\u770b\u5230 HasMaxLength \u65b9\u6cd5\u94fe\u63a5\u5230 HasColumnName \u65b9\u6cd5\u7684 Fluent API\u3002<\/p>\n
    8.2 \u8fc1\u79fb<\/h2>\n
    \u60a8\u51e0\u4e4e\u53ef\u4ee5\u521b\u5efa\u8fc1\u79fb\uff0c\u4f7f\u6570\u636e\u5e93\u67b6\u6784\u4e0e\u6a21\u578b\u4fdd\u6301\u540c\u6b65\u3002\u8fc1\u79fb\u5de5\u5177\u68c0\u67e5\u4e0a\u4e0b\u6587\u7684 DbSet \u5c5e\u6027\uff0c\u5e76\u5c06\u5b83\u4eec\u4e0e\u4e0a\u4e00\u4e2a\u8fc1\u79fb\u751f\u6210\u7684\u5feb\u7167\uff08\u5982\u679c\u6709\uff09\u8fdb\u884c\u6bd4\u8f83\u3002\u4efb\u4f55\u5dee\u5f02\u90fd\u4f1a\u5bfc\u81f4\u751f\u6210 C# \u4ee3\u7801\uff0c\u8fd9\u4e9b\u4ee3\u7801\u5728\u6267\u884c\u65f6\u88ab\u8f6c\u6362\u4e3a SQL\uff0c\u8be5 SQL \u5c06\u66f4\u6539\u5e94\u7528\u4e8e\u5b9e\u9645\u6570\u636e\u5e93\u3002\u5982\u679c\u6570\u636e\u5e93\u5c1a\u4e0d\u5b58\u5728\uff0c\u5219\u7b2c\u4e00\u6b21\u8fc1\u79fb\u5c06\u5bfc\u81f4\u521b\u5efa\u6570\u636e\u5e93\u3002\u8fd8\u53ef\u4ee5\u6309\u9700\u751f\u6210\u8fc1\u79fb SQL \u811a\u672c\uff0c\u56e0\u6b64\u60a8\u53ef\u4ee5\u81ea\u884c\u5c06\u5b83\u4eec\u5e94\u7528\u4e8e\u6570\u636e\u5e93\u3002\u8fd9\u5bf9\u4e8e\u5bf9\u5b9e\u65f6\u6570\u636e\u5e93\u8fdb\u884c\u66f4\u6539\u7279\u522b\u6709\u7528\uff0c\u56e0\u4e3a\u5728\u5b9e\u65f6\u6570\u636e\u5e93\u4e2d\uff0c\u6267\u884c C# \u4ee3\u7801\u901a\u5e38\u5f88\u56f0\u96be\uff08\u5982\u679c\u4e0d\u662f\u4e0d\u53ef\u80fd\u7684\u8bdd\uff09\u3002<\/p>\n
    \u914d\u7f6e\u7684\u53e6\u4e00\u4e2a\u975e\u5e38\u6709\u7528\u7684\u65b9\u9762\u662f\u6307\u5b9a\u79cd\u5b50\u6570\u636e\u7684\u80fd\u529b\uff0c\u8be5\u6570\u636e\u7528\u4e8e\u5728\u8fc1\u79fb\u671f\u95f4\u586b\u5145\u6570\u636e\u5e93\u3002\u6b64\u529f\u80fd\u5177\u6709\u660e\u663e\u7684\u7528\u9014\uff0c\u56e0\u4e3a\u5b83\u53ef\u4ee5\u8ba9\u60a8\u5f00\u59cb\u4f7f\u7528\u4e00\u7ec4\u6570\u636e\uff0c\u800c\u65e0\u9700\u624b\u52a8\u8f93\u5165\u3002\u5728\u4e0b\u4e00\u8282\u4e2d\uff0c\u60a8\u5c06\u4e86\u89e3\u5982\u4f55\u5c06\u6b64\u529f\u80fd\u4e0e\u4e00\u4e9b\u56fd\u5bb6\/\u5730\u533a\u6570\u636e\u4e00\u8d77\u4f7f\u7528\uff0c\u7136\u540e\u662f\u4e00\u4e9b\u57ce\u5e02\u6570\u636e\u3002<\/p>\n
    \u672c\u7ae0 \uff08http:\/\/mng.bz\/jAra<\/a>\uff09 \u9644\u5e26\u7684\u8fc1\u79fb\u4e0b\u8f7d\u8fd8\u5305\u62ec Property \u7c7b\u578b\u7684\u79cd\u5b50\u6570\u636e\u4ee5\u53ca cities \u7684\u4e00\u4e9b\u56fe\u50cf\uff08\u7531 https:\/\/unsplash.com\/<\/a> \u63d0\u4f9b\uff09\u3002\u6211\u5efa\u8bae\u60a8\u4ece GitHub \u5b58\u50a8\u5e93\u83b7\u53d6\u76f8\u5173\u4ee3\u7801\u548c\u56fe\u50cf\uff0c\u5e76\u5c06\u5176\u7528\u4e8e\u8fc1\u79fb\uff0c\u4ee5\u4fbf\u60a8\u7684\u6570\u636e\u5e93\u5185\u5bb9\u4e0e\u4ee5\u540e\u7684\u793a\u4f8b\u76f8\u5339\u914d\u3002<\/p>\n
    8.2.1 \u79cd\u5b50\u6570\u636e<\/h3>\n
    \u60a8\u5c06\u4f7f\u7528 Fluent API HasData \u65b9\u6cd5\u4e3a\u5b9e\u4f53\u6307\u5b9a\u79cd\u5b50\u6570\u636e\uff0c\u4f5c\u4e3a\u5176\u914d\u7f6e\u7684\u4e00\u90e8\u5206\u3002\u60a8\u5fc5\u987b\u6307\u5b9a\u4e3b\u952e\u503c\u548c\u5916\u952e\u503c\uff0c\u4ee5\u4fbf\u8fc1\u79fb\u53ef\u4ee5\u786e\u5b9a\u662f\u5426\u5728\u8fc1\u79fb\u4e4b\u5916\u5bf9\u6570\u636e\u8fdb\u884c\u4e86\u4efb\u4f55\u66f4\u6539\u3002\u6b64\u7c7b\u66f4\u6539\u5c06\u88ab\u8986\u76d6\uff0c\u56e0\u6b64\u79cd\u5b50\u8bbe\u5b9a\u529f\u80fd\u6700\u9002\u5408\u4e8e\u4e0d\u4f1a\u66f4\u6539\u7684\u9759\u6001\u6570\u636e\u3002\u5982\u679c\u6570\u636e\u5728\u4f7f\u7528\u79cd\u5b50\u8bbe\u5b9a\u529f\u80fd\u6dfb\u52a0\u540e\u53ef\u80fd\u4f1a\u66f4\u6539\uff0c\u5219\u53ef\u4ee5\u6ce8\u91ca\u6389\u76f8\u5173\u4ee3\u7801\uff0c\u8fd9\u6837\u5c31\u4e0d\u4f1a\u5728\u540e\u7eed\u8fc1\u79fb\u4e2d\u8c03\u7528\u5b83\u3002\u4e0b\u9762\u7684\u6e05\u5355\u663e\u793a\u4e86 CountryConfiguration \u7c7b\u4e2d\u7684 Configure \u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u7ecf\u8fc7\u4fee\u6539\u540e\u5305\u62ec HasData \u65b9\u6cd5\u8c03\u7528\uff0c\u8be5\u65b9\u6cd5\u91c7\u7528\u76f8\u5173\u7c7b\u578b\u7684\u96c6\u5408\u3002<\/p>\n
    \u6e05\u5355 8.10 \u56fd\u5bb6\u79cd\u5b50\u6570\u636e<\/p>\n
    public void Configure(EntityTypeBuilder<Country> builder)\n{\n    builder.Property(x => x.CountryName)\n        .HasMaxLength(50);\n    builder.Property(x => x.CountryCode)\n        .HasColumnName("ISO 3166 code")\n        .HasMaxLength(2);\n    builder.HasData(new List<Country>\n    {\n        new Country {Id = 1, CountryName = "Croatia", CountryCode="hr" },\n        new Country {Id = 2, CountryName = "Denmark", CountryCode =  "dk" },\n        new Country {Id = 3, CountryName = "France", CountryCode = "fr" },\n        new Country {Id = 4, CountryName = "Germany", CountryCode = "de" },\n        new Country {Id = 5, CountryName = "Holland", CountryCode = "nl" },\n        new Country {Id = 6, CountryName = "Italy", CountryCode = "it" },\n        new Country {Id = 7, CountryName = "Spain", CountryCode = "es" },\n        new Country {Id = 8, CountryName = "United Kingdom", \n        \u27a5 CountryCode = "gb" },\n        new Country {Id = 9, CountryName = "United States", \n        \u27a5 CountryCode = "us" }\n    });\n}<\/code><\/pre>\n
    \u8981\u4e3a\u57ce\u5e02\u6dfb\u52a0\u79cd\u5b50\u6570\u636e\uff0c\u60a8\u9996\u5148\u9700\u8981\u5411 City \u7c7b\u6dfb\u52a0\u4e00\u4e2a\u5c5e\u6027\u6765\u8868\u793a\u56fe\u50cf\u3002\u6211\u5c06\u6b64\u5c5e\u6027\u547d\u540d\u4e3a Photo\uff0c\u4f46\u60a8\u9700\u8981\u5c06\u5176\u914d\u7f6e\u4e3a\u6620\u5c04\u5230\u540d\u4e3a Image \u7684\u5217\u3002<\/p>\n
    \u793a\u4f8b 8.11 \u5411 City \u7c7b\u6dfb\u52a0 Photo \u5c5e\u6027<\/p>\n
    public class City\n{\n    public int Id { get; set; }\n    public string Name { get; set; }\n    public string Photo { get; set; }\n    public int CountryId { get; set; }\n    public Country Country { get; set; }\n    public List<Property> Properties {  get; set; } = new List<Property>();\n}<\/code><\/pre>\n
    \u73b0\u5728\uff0c\u60a8\u9700\u8981\u5c06\u53e6\u4e00\u4e2a IEntityTypeConfiguration \u7c7b\u6dfb\u52a0\u5230 Configuration \u6587\u4ef6\u5939\uff0c\u8fd9\u6b21\u540d\u4e3a CityConfiguration\uff0c\u4ee3\u7801\u5982\u4e0b\u3002<\/p>\n
    \u5217\u8868 8.12 City \u914d\u7f6e\u7c7b<\/p>\n
    using CityBreaks.Models;\nusing Microsoft.EntityFrameworkCore;\nusing Microsoft.EntityFrameworkCore.Metadata.Builders;\n\nnamespace CityBreaks.Data.Configuration;\npublic class CityConfiguration : IEntityTypeConfiguration<City>\n{\n    public void Configure(EntityTypeBuilder<City> builder)\n    {\n        builder.Property(x => x.Photo).HasColumnName("Image");\n        builder.HasData(new List<City>\n        {\n            new City { Id = 1, Name = "Amsterdam", CountryId = 5, \n            \u27a5 Photo = "amsterdam.jpg" },\n            new City { Id = 2, Name = "Barcelona", CountryId = 7, \n            \u27a5 Photo ="barcelona.jpg" },\n            new City { Id = 3, Name = "Berlin", CountryId = 4, \n            \u27a5 Photo ="berlin.jpg" },\n            new City { Id = 4, Name = "Copenhagen", CountryId = 2, \n            \u27a5 Photo ="copenhagen.jpg" },\n            new City { Id = 5, Name = "Dubrovnik", CountryId = 1, \n            \u27a5 Photo ="dubrovnik.jpg" },\n            new City { Id = 6, Name = "Edinburgh", CountryId = 8, \n            \u27a5 Photo ="edinburgh.jpg" },\n            new City { Id = 7, Name = "London", CountryId = 8, \n            \u27a5 Photo ="london.jpg" },\n            new City { Id = 8, Name = "Madrid", CountryId = 7, \n            \u27a5 Photo ="madrid.jpg" },\n            new City { Id = 9, Name = "New York", CountryId = 9, \n            \u27a5 Photo ="new-york.jpg" },\n            new City { Id = 10, Name = "Paris", CountryId = 3, \n            \u27a5 Photo ="paris.jpg" },\n            new City { Id = 11, Name = "Rome", CountryId = 6, \n            \u27a5 Photo ="rome.jpg" },\n            new City { Id = 12, Name = "Venice", CountryId = 6, \n            \u27a5 Photo ="venice.jpg" }\n        });\n    }\n}<\/code><\/pre>\n
    \u8bf7\u6ce8\u610f\uff0c\u60a8\u5df2\u4f7f\u7528 HasColumnName \u65b9\u6cd5\u5c06 Photo \u5c5e\u6027\u6620\u5c04\u5230\u540d\u4e3a Image \u7684\u5217\u3002<\/p>\n
    \u6700\u7ec8\u914d\u7f6e\u9002\u7528\u4e8e Property \u7c7b\u578b\u3002\u6b64\u914d\u7f6e\u5b8c\u5168\u7531\u79cd\u5b50\u6570\u636e\u7ec4\u6210\uff0c\u8be5\u4e66\u4e0b\u8f7d\u4e2d\u7684\u793a\u4f8b\u5305\u62ec 50 \u4e2a\u865a\u6784\u7684\u5c5e\u6027\u8be6\u7ec6\u4fe1\u606f\u3002\u60a8\u53ef\u4ee5\u6839\u636e\u76ee\u524d\u6240\u5b66\u7684\u77e5\u8bc6\u751f\u6210\u79cd\u5b50\u6570\u636e\uff0c\u4e5f\u53ef\u4ee5\u4ece\u672c\u4e66\u7684 GitHub \u5b58\u50a8\u5e93 http:\/\/mng.bz\/yaBd<\/a> \u590d\u5236\u914d\u7f6e\u6587\u4ef6\u7684\u5185\u5bb9\u3002<\/p>\n
    \u5b8c\u6210\u914d\u7f6e\u7c7b\u540e\uff0c\u60a8\u9700\u8981\u5411 DbContext \u6ce8\u518c\u5b83\u4eec\u3002\u4e3a\u6b64\uff0c\u60a8\u53ef\u4ee5\u91cd\u5199 CityBreaksContext \u7c7b\u4e2d\u7684 OnModelCreating \u65b9\u6cd5\uff0c\u7136\u540e\u4f7f\u7528 ModelBuilder ApplyConfiguration \u65b9\u6cd5\u6ce8\u518c\u6bcf\u4e2a\u7c7b\u578b\u3002\u7531\u4e8e ApplyConfiguration \u65b9\u6cd5\u8fd4\u56de ModelBuilder\uff0c\u56e0\u6b64\u60a8\u53ef\u4ee5\u94fe\u63a5\u8fd9\u4e9b\u8c03\u7528\u3002<\/p>\n
    \u793a\u4f8b 8.13 \u5728 OnModelCreating \u65b9\u6cd5\u4e2d\u6ce8\u518c\u914d\u7f6e<\/p>\n
    protected override void OnModelCreating (ModelBuilder builder)\n{\n    builder\n        .ApplyConfiguration(new CityConfiguration())\n        .ApplyConfiguration(new CountryConfiguration())\n        .ApplyConfiguration(new PropertyConfiguration());\n}<\/code><\/pre>\n
    8.2.2 \u6dfb\u52a0\u8fc1\u79fb\u5de5\u5177<\/h3>\n
    \u5728\u521b\u5efa\u8fc1\u79fb\u4e4b\u524d\uff0c\u60a8\u9700\u8981\u5c06\u5fc5\u8981\u7684\u5305\u6dfb\u52a0\u5230\u5305\u542b\u7528\u4e8e\u7ba1\u7406\u8fc1\u79fb\u7684\u547d\u4ee4\u7684\u9879\u76ee\u4e2d\u3002\u6709\u4e24\u4e2a\u8f6f\u4ef6\u5305\u53ef\u7528\uff0c\u6bcf\u4e2a\u8f6f\u4ef6\u5305\u90fd\u6709\u4e00\u7ec4\u4e0d\u540c\u7684\u547d\u4ee4\u3002\u60a8\u4f7f\u7528\u7684 ID \u53d6\u51b3\u4e8e\u60a8\u8981\u7528\u4e8e\u6267\u884c\u8fc1\u79fb\u547d\u4ee4\u7684\u5de5\u5177\u3002<\/p>\n
    \u5982\u679c\u60a8\u662f Visual Studio \u7528\u6237\uff0c\u5219\u53ef\u4ee5\u4f7f\u7528 Package Manager \u63a7\u5236\u53f0;\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u60a8\u5c06\u9700\u8981 PowerShell \u547d\u4ee4\u5305\u542b\u5728 Microsoft.EntityFrameworkCore.Tools \u5305\u4e2d\u3002\u6216\u8005\uff0c\u60a8\u4e5f\u53ef\u4ee5\u6539\u7528 Microsoft.EntityFrameworkCore.Design \u8f6f\u4ef6\u5305\u4e2d\u63d0\u4f9b\u7684\u8de8\u5e73\u53f0 CLI \u547d\u4ee4\u3002\u9009\u62e9\u5305\u540e\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528\u524d\u9762\u4ecb\u7ecd\u7684\u90a3\u4e9b\u60a8\u559c\u6b22\u7684\u65b9\u6cd5\u5c06\u5305\u6dfb\u52a0\u5230\u9879\u76ee\u4e2d\u3002\u5982\u679c\u60a8\u4f7f\u7528\u7684\u662f CLI \u547d\u4ee4\uff0c\u5219\u8fd8\u5fc5\u987b\u786e\u4fdd\u5168\u5c40\u5b89\u88c5 dotnet-ef \u5de5\u5177\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u6267\u884c\u6b64\u4f5c\uff1a<\/p>\n
    dotnet tool install --global dotnet-ef<\/code><\/pre>\n
    8.2.3 \u521b\u5efa\u548c\u5e94\u7528\u8fc1\u79fb<\/h3>\n
    \u5b89\u88c5\u5de5\u5177\u548c\u76f8\u5173\u5305\u540e\uff0c\u60a8\u53ef\u4ee5\u521b\u5efa\u60a8\u7684\u7b2c\u4e00\u4e2a\u8fc1\u79fb\u3002\u60a8\u5c06\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u4e4b\u4e00\uff1a<\/p>\n
    [Powershell]                       \u2776\nadd-migration Create               \u2776\n[CLI]                              \u2777\ndotnet ef migrations ad Create     \u2777<\/code><\/pre>\n
    \u2776 \u8981\u4ece Visual Studio \u7684\u5305\u7ba1\u7406\u5668\u63a7\u5236\u53f0\u4e2d\u6267\u884c\u7684 PowerShell \u547d\u4ee4<\/p>\n
    \u2777 \u8981\u4ece\u5305\u542b csproj \u6587\u4ef6\u7684\u76ee\u5f55\u4e2d\u7684\u547d\u4ee4\u63d0\u793a\u7b26\u6267\u884c\u7684 CLI \u547d\u4ee4<\/p>\n
    \u8fc1\u79fb\u540d\u4e3a Create\u3002\u6210\u529f\u6267\u884c\u60a8\u4f7f\u7528\u7684\u4efb\u4f55\u547d\u4ee4\u90fd\u4f1a\u5bfc\u81f4\u5c06\u4e00\u4e2a\u540d\u4e3a Migrations \u7684\u65b0\u6587\u4ef6\u5939\u6dfb\u52a0\u5230\u9879\u76ee\u4e2d\u3002\u56fe 8.5 \u663e\u793a\u4e86 Visual Studio Code \u6587\u4ef6\u8d44\u6e90\u7ba1\u7406\u5668\u4e2d\u7684 Migrations \u6587\u4ef6\u5939\u53ca\u5176\u5185\u5bb9\u3002<\/p>\n
    <\/p>\n
    \u56fe 8.5 \u751f\u6210\u7684 Migrations \u6587\u4ef6\u5939\uff0c\u5305\u542b\u4e09\u4e2a\u6587\u4ef6<\/p>\n
    \u65b0\u6587\u4ef6\u5939\u5305\u542b\u4e09\u4e2a\u6587\u4ef6\uff1a<\/p>\n
      \n
    1. [Timestamp]_Create.cs - \u5305\u542b\u4e00\u4e2a\u540d\u4e3a Create \u7684\u7c7b\uff0c\u8be5\u7c7b\u5177\u6709\u4e24\u4e2a\u65b9\u6cd5\uff1aUp \u548c Down\u3002Up \u65b9\u6cd5\u5c06\u66f4\u6539\u5e94\u7528\u4e8e\u6570\u636e\u5e93\uff0c\u800c Down \u65b9\u6cd5\u5219\u8fd8\u539f\u8fd9\u4e9b\u66f4\u6539\u3002<\/li>\n
    2. [Timestamp]_Create.Designer.cs - \u5305\u542b EF Core \u4f7f\u7528\u7684\u5143\u6570\u636e\u3002<\/li>\n
    3. CityBreaksContextModelSnapshot.cs - \u6a21\u578b\u7684\u5f53\u524d\u5feb\u7167\u3002\u5f53\u60a8\u6dfb\u52a0\u53e6\u4e00\u4e2a\u8fc1\u79fb\u65f6\uff0c\u6b64\u5feb\u7167\u5c06\u7528\u4f5c\u57fa\u51c6\u6765\u786e\u5b9a\u5df2\u66f4\u6539\u7684\u5185\u5bb9\u3002<\/li>\n<\/ol>\n
      \u524d\u4e24\u4e2a\u6587\u4ef6\u7279\u5b9a\u4e8e\u8fc1\u79fb\u3002\u5c06\u4e3a\u5176\u4ed6\u8fc1\u79fb\u6dfb\u52a0\u65b0\u7684 VPN\u3002\u6a21\u578b\u5feb\u7167\u6587\u4ef6\u5c06\u9488\u5bf9\u6bcf\u6b21\u65b0\u7684\u8fc1\u79fb\u8fdb\u884c\u66f4\u65b0\u3002\u5982\u679c\u67e5\u770b\u7b2c\u4e00\u4e2a\u6587\u4ef6\u4e2d Up \u65b9\u6cd5\u7684\u5185\u5bb9\uff0c\u5219 C# \u4ee3\u7801\u5e94\u8be5\u662f\u4e0d\u8a00\u81ea\u660e\u7684\u3002\u5728\u5c06\u8fc1\u79fb\u5e94\u7528\u5230\u6570\u636e\u5e93\u4e4b\u524d\uff0c\u60a8\u53ef\u4ee5\u6839\u636e\u9700\u8981\u81ea\u7531\u4fee\u6539\u6b64\u7248\u672c\u3002\u4f8b\u5982\uff0c\u5728\u4ee5\u540e\u7684\u8fc1\u79fb\u4e2d\uff0c\u60a8\u53ef\u80fd\u5e0c\u671b\u80fd\u591f\u5728\u8fc7\u7a0b\u4e2d\u6267\u884c\u4e00\u4e9b\u81ea\u5b9a\u4e49 SQL\uff0c\u4f8b\u5982\u5f15\u5165\u975e\u79cd\u5b50\u6570\u636e\u3002\u5728\u672c\u4e66\u4e2d\uff0c\u6211\u6ca1\u6709\u4ecb\u7ecd\u8fd9\u4e00\u70b9\uff0c\u4f46\u77e5\u9053\u8be5\u529f\u80fd\u5728\u60a8\u9700\u8981\u65f6\u53ef\u7528\u662f\u5f88\u6709\u7528\u7684\u3002\u4f46\u662f\uff0c\u6211\u901a\u5e38\u4f1a\u67e5\u770b\u8fc1\u79fb\u4ee3\u7801\uff0c\u4ee5\u786e\u4fdd\u6211\u6253\u7b97\u5e94\u7528\u7684\u66f4\u6539\u53cd\u6620\u5728\u90a3\u91cc\u3002\u4e0d\u6b62\u4e00\u6b21\uff0c\u901a\u8fc7\u67e5\u770b\u8fc1\u79fb\u4ee3\u7801\uff0c\u6211\u610f\u8bc6\u5230\u6211\u6ca1\u6709\u6b63\u786e\u914d\u7f6e\u5c5e\u6027\u3002\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u60a8\u53ef\u4ee5\u8c03\u6574\u6a21\u578b\u914d\u7f6e\uff0c\u7136\u540e\u4f7f\u7528 remove-migration \uff08PowerShell\uff09 \u6216 dotnet ef migrations remove \uff08CLI\uff09 \u547d\u4ee4\u5220\u9664\u73b0\u6709\u8fc1\u79fb\uff0c\u7136\u540e\u518d\u4f7f\u7528\u4e0e\u4ee5\u524d\u76f8\u540c\u7684\u547d\u4ee4\u5c06\u5176\u6dfb\u52a0\u56de\u53bb\u3002<\/p>\n
      \u751f\u6210\u8fc1\u79fb\u5e76\u68c0\u67e5\u5b83\u662f\u5426\u6309\u60a8\u7684\u8981\u6c42\u8fd0\u884c\u540e\uff0c\u60a8\u5c06\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u4e4b\u4e00\u5e94\u7528\u5b83\uff1a<\/p>\n
      [Powershell]\nupdate-database\n[CLI]\ndotnet ef database update<\/code><\/pre>\n
      \u6267\u884c\u8fd9\u4e9b\u547d\u4ee4\u4e4b\u4e00\u540e\uff0c\u60a8\u5e94\u8be5\u4f1a\u770b\u5230\u5df2\u5728 Data \u6587\u4ef6\u5939\u4e2d\u521b\u5efa\u4e86\u4e00\u4e2a SQLite \u6570\u636e\u5e93\u6587\u4ef6\uff1aCityBreaks.db\u3002\u4f7f\u7528\u60a8\u559c\u6b22\u7684\u4efb\u4f55\u5de5\u5177\uff08\u6211\u4f7f\u7528 SQLite \u7684\u8de8\u5e73\u53f0 DB \u6d4f\u89c8\u5668;https:\/\/sqlitebrowser.org\/\uff09\uff0c\u8bf7\u67e5\u770b<\/a> schema\uff08\u56fe 8.6\uff09\u3002\u9664\u4e86\u6bcf\u4e2a\u6a21\u578b\u7c7b\u7684\u8868\u4e4b\u5916\uff0c\u6570\u636e\u5e93\u8fd8\u5305\u62ec\u4e00\u4e2a\u540d\u4e3a __EFMigrationsHistory \u7684\u8868\u3002<\/p>\n
      <\/p>\n
      \u56fe 8.6 \u65b0\u6570\u636e\u5e93\u5305\u542b\u540d\u4e3a __EFMigrationsHistory \u7684\u8868\u3002<\/p>\n
      \u6b64\u8868\u8ddf\u8e2a\u5df2\u5e94\u7528\u4e8e\u6570\u636e\u5e93\u7684\u8fc1\u79fb\u3002\u76ee\u524d\uff0c\u5b83\u5305\u542b\u4e00\u6761\u8bb0\u5f55\uff0c\u8be5\u8bb0\u5f55\u7531\u60a8\u521a\u521a\u5e94\u7528\u7684\u8fc1\u79fb\u7684\u540d\u79f0\u4ee5\u53ca\u4f7f\u7528\u7684 EF Core \u7248\u672c\u7ec4\u6210\u3002<\/p>\n
      8.3 \u67e5\u8be2\u6570\u636e<\/h2>\n
      \u60a8\u7684\u6570\u636e\u5e93\u5df2\u586b\u5145\u79cd\u5b50\u6570\u636e\uff0c\u73b0\u5728\u662f\u5f00\u59cb\u4f7f\u7528\u5b83\u7684\u65f6\u5019\u4e86\u3002\u4f60\u5c06\u4f7f\u7528 LINQ \u6765\u8868\u8fbe\u4f60\u5e0c\u671b EF Core \u5bf9\u6570\u636e\u5e93\u6267\u884c\u7684\u547d\u4ee4\u3002LINQ \u5305\u542b\u4e00\u7ec4 IEnumerable \u7c7b\u578b\u7684\u6269\u5c55\u65b9\u6cd5\uff0c\u8fd9\u4e9b\u65b9\u6cd5\u652f\u6301\u5bf9\u96c6\u5408\u8fdb\u884c\u9009\u62e9\u548c\u7b5b\u9009\u4f5c\u3002\u60a8\u4f5c\u7684\u96c6\u5408\u662f\u4e0a\u4e0b\u6587\u4e2d\u7684 DbSet \u5bf9\u8c61\u3002<\/p>\n
      EF Core \u8d1f\u8d23\u5c06 LINQ \u67e5\u8be2\u8f6c\u6362\u4e3a\u8981\u9488\u5bf9\u6570\u636e\u5e93\u6267\u884c\u7684 SQL\u3002\u751f\u6210\u7684 SQL \u53d6\u51b3\u4e8e\u6240\u4f7f\u7528\u7684\u63d0\u4f9b\u7a0b\u5e8f\uff0c\u540c\u65f6\u8003\u8651\u5230\u7279\u5b9a\u4e8e\u6570\u636e\u5e93\u7684\u529f\u80fd\u3002<\/p>\n
      \u5728\u7f16\u5199 LINQ \u67e5\u8be2\u65f6\uff0c\u53ef\u4ee5\u91c7\u7528\u4ee5\u4e0b\u4e24\u79cd\u65b9\u6cd5\u4e4b\u4e00\u3002\u60a8\u53ef\u4ee5\u4f7f\u7528 query \u8bed\u6cd5\u6216 method \u8bed\u6cd5\u3002\u67e5\u8be2\u8bed\u6cd5\u770b\u8d77\u6765\u7c7b\u4f3c\u4e8e SQL \u8bed\u53e5\uff0c\u6709\u4e9b\u4eba\u5bf9\u5b83\u611f\u89c9\u66f4\u8212\u670d\u3002\u4ee5\u4e0b\u793a\u4f8b\u663e\u793a\u4e86\u7528\u4e8e\u83b7\u53d6\u5c5e\u4e8e\u4e3b\u952e\u503c\u4e3a 1 \u7684\u56fd\u5bb6\/\u5730\u533a\u7684\u6240\u6709\u57ce\u5e02\u7684\u67e5\u8be2\u8bed\u6cd5\uff1a<\/p>\n
      var data = from c in _context.Cities where c.CountryId == 1 select c;<\/code><\/pre>\n
      \u4f46\u662f\uff0c\u5c31\u50cf\u6570\u636e\u6ce8\u91ca\u5c5e\u6027\u4ec5\u63d0\u4f9b\u6a21\u578b\u914d\u7f6e\u9009\u9879\u7684\u5b50\u96c6\u4e00\u6837\uff0c\u67e5\u8be2\u8bed\u6cd5\u5e76\u4e0d\u603b\u662f\u8db3\u591f\u7684\u3002\u67d0\u4e9b\u67e5\u8be2\u53ea\u80fd\u4f7f\u7528\u65b9\u6cd5\u8c03\u7528\u6765\u8868\u793a\u3002<\/p>\n
      \u6211\u66f4\u559c\u6b22\u65b9\u6cd5\u8bed\u6cd5\uff0c\u5b83\u5305\u62ec\u5c06\u8c03\u7528\u94fe\u63a5\u5230 IEnumerable \u7c7b\u578b \uff08http:\/\/mng.bz\/M0RB<\/a>\uff09 \u4e0a\u7684\u6269\u5c55\u65b9\u6cd5\u3002\u4f7f\u7528\u67e5\u8be2\u8bed\u6cd5\uff0c\u60a8\u7684\u4ee3\u7801\u5728\u7f16\u8bd1\u65f6\u4f1a\u8f6c\u6362\u4e3a\u65b9\u6cd5\u8c03\u7528\uff0c\u56e0\u6b64\u8fd9\u4e24\u79cd\u65b9\u6cd5\u4e4b\u95f4\u6ca1\u6709\u6027\u80fd\u5dee\u5f02\u3002\u5728\u672c\u4e66\u4e2d\uff0c\u6211\u4eec\u53ea\u4f7f\u7528\u65b9\u6cd5\u8bed\u6cd5\u3002\u5982\u679c\u60a8\u6709\u5174\u8da3\u4e86\u89e3\u6709\u5173\u67e5\u8be2\u8bed\u6cd5\u7684\u66f4\u591a\u4fe1\u606f\uff0c\u5b98\u65b9 LINQ \u6587\u6863\u63d0\u4f9b\u4e86\u8bb8\u591a\u793a\u4f8b\uff1ahttp:\/\/mng.bz\/aPNm<\/a>\u3002<\/p>\n
      8.3.1 \u68c0\u7d22\u591a\u6761\u8bb0\u5f55<\/h3>\n
      \u60a8\u8981\u505a\u7684\u7b2c\u4e00\u4ef6\u4e8b\u662f\u4e3a\u57ce\u5e02\u521b\u5efa\u4e00\u4e2a\u65b0\u670d\u52a1\uff0c\u8fd9\u4e9b\u57ce\u5e02\u5c06\u4f7f\u7528\u6570\u636e\u5e93\u4f5c\u4e3a\u5176\u6570\u636e\u6e90\u3002\u5c06\u4e00\u4e2a\u65b0\u7684\u7c7b\u6587\u4ef6\u6dfb\u52a0\u5230 Services \u6587\u4ef6\u5939\uff0c\u5c06\u6b64\u7c7b\u6587\u4ef6\u547d\u540d\u4e3a CityService.cs\u3002\u6b64\u7c7b\u5c06\u5b9e\u73b0\u60a8\u5728\u4e0a\u4e00\u7ae0\u4e2d\u521b\u5efa\u7684 ICityService \u63a5\u53e3\uff0c\u5e76\u5c06 CityBreaksContext \u4f5c\u4e3a\u4f9d\u8d56\u9879\u3002\u8be5\u7c7b\u7684\u521d\u59cb\u4ee3\u7801\u5982\u4e0b\u9762\u7684\u6e05\u5355\u6240\u793a\u3002<\/p>\n
      Listing 8.14 CityService \u7c7b<\/p>\n
      using CityBreaks.Data;\nusing CityBreaks.Models;\nusing Microsoft.EntityFrameworkCore;\n\nnamespace CityBreaks.Services;\npublic class CityService : ICityService\n{\n    private readonly CityBreaksContext _context;\n    public CityService(CityBreaksContext context) => _context = context;\n    public async Task<List<City>> GetAllAsync()\n    {\n        var cities = _context.Cities             \u2776\n            .Include(c => c.Country)             \u2777\n            .Include(c => c.Properties);         \u2777\n        return await cities.ToListAsync();       \u2778\n    }\n}<\/code><\/pre>\n
      \u2776 \u67e5\u8be2\u7684\u5165\u53e3\u70b9\u662f DbSet\u3002
      \n\u2777 \u4f7f\u7528 Include \u65b9\u6cd5\u6307\u5b9a\u8981\u5305\u542b\u5728\u67e5\u8be2\u4e2d\u7684\u76f8\u5173\u6570\u636e\u3002
      \n\u2778 ToListAsync \u65b9\u6cd5\u8c03\u7528\u4f1a\u5bfc\u81f4\u67e5\u8be2\u6267\u884c\u3002<\/p>\n
      LINQ \u67e5\u8be2\u7531\u4e24\u4e2a\u9636\u6bb5\u7ec4\u6210\uff1a\u89c4\u8303\u9636\u6bb5\u548c\u6267\u884c\u9636\u6bb5\u3002\u5728\u6211\u4eec\u7684\u793a\u4f8b\u4e2d\uff0c\u67e5\u8be2\u7684\u89c4\u8303\u53d1\u751f\u5728 GetAllAsync \u65b9\u6cd5\u7684\u524d\u4e09\u884c\u4e2d\u3002\u6267\u884c\u5c06\u5ef6\u8fdf\u5230\u6700\u540e\u4e00\u884c\uff0c\u6b64\u65f6\u8c03\u7528 ToListAsync \u65b9\u6cd5\u3002\u53ea\u6709\u5728\u8be5\u70b9\u4e0a\uff0c\u624d\u4f1a\u8c03\u7528\u6570\u636e\u5e93\u3002\u8fd9\u79cd\u5ef6\u8fdf\u6267\u884c\u7684\u80fd\u529b\u4f7f\u60a8\u80fd\u591f\u901a\u8fc7\u6dfb\u52a0\u5176\u4ed6\u6761\u4ef6\u6765\u7ee7\u7eed\u7f16\u5199\u89c4\u8303\u3002\u4f8b\u5982\uff0c\u60a8\u53ef\u80fd\u5e0c\u671b\u7b5b\u9009\u67e5\u8be2\u4ee5\u4ec5\u8fd4\u56de\u6cd5\u56fd\u7684\u57ce\u5e02\uff0c\u60a8\u53ef\u4ee5\u5728\u91c7\u7528\u8868\u793a\u7b5b\u9009\u6761\u4ef6\u7684\u8c13\u8bcd\u7684 Where \u65b9\u6cd5\u8c03\u7528\u4e2d\u6267\u884c\u6b64\u4f5c\uff1a<\/p>\n
      var cities = _context.Cities\n    .Where(c => c.Country.CountryName == "France")\n    .Include(c => c.Country)\n    .Include(c => c.Properties);<\/code><\/pre>\n
      \u60a8\u5e0c\u671b\u8fd4\u56de\u6240\u6709\u57ce\u5e02\uff0c\u5305\u62ec\u5176\u76f8\u5173\u7684\u56fd\u5bb6\/\u5730\u533a\u548c\u5c5e\u6027\uff0c\u4ee5\u4fbf\u60a8\u53ef\u4ee5\u5728\u5e94\u7528\u7a0b\u5e8f\u7684\u4e3b\u9875\u4e0a\u663e\u793a\u8be6\u7ec6\u4fe1\u606f\u3002\u4f46\u662f\uff0c\u60a8\u53ea\u60f3\u5305\u542b\u5f53\u524d\u53ef\u7528\u7684\u5c5e\u6027\uff0c\u56e0\u6b64\u5c06\u8fc7\u6ee4\u5668\u5e94\u7528\u4e8e Include \u65b9\u6cd5\uff1a<\/p>\n
      var cities = _context.Cities\n    .Include(c => c.Country)\n    .Include(c => c.Properties.Where(p => p.AvailableFrom < DateTime.Now));<\/code><\/pre>\n
      \u4e0b\u4e00\u6b65\u662f\u66f4\u65b0 Index.cshtml.cs \u6587\u4ef6\u5185\u5bb9\uff0c\u5e76\u5c06\u73b0\u6709\u5185\u5bb9\u66ff\u6362\u4e3a\u4ee5\u4e0b\u4ee3\u7801\uff0c\u8be5\u4ee3\u7801\u5c06 ICityService \u6ce8\u5165\u6784\u9020\u51fd\u6570\u4e2d\uff0c\u5e76\u4f7f\u7528\u5b83\u6765\u83b7\u53d6\u57ce\u5e02\u6570\u636e\u3002<\/p>\n
      \u6e05\u5355 8.15 \u4fee\u6539\u540e\u7684 Index Model \u4e3b\u9875\u4ee3\u7801<\/p>\n
      using CityBreaks.Models;\nusing CityBreaks.Services;\nusing Microsoft.AspNetCore.Mvc.RazorPages;\n\nnamespace CityBreaks.Pages\n{\n    public class IndexModel : PageModel\n    {\n        private readonly ICityService _cityService;\n\n        public IndexModel(ICityService cityService)\n        {\n           _cityService = cityService;  \n        }\n\n        public List<City> Cities { get; set; }\n        public async Task OnGetAsync() => Cities = \n        \u27a5 await _cityService.GetAllAsync();\n    }\n}<\/code><\/pre>\n
      \u7136\u540e\uff0c\u4ece\u4e3b\u9875\u4e2d\u5220\u9664\u5217\u8868\u6846\uff08\u5982\u679c\u7b2c 5 \u7ae0\u4e2d\u5b83\u4ecd\u7136\u5b58\u5728\uff09\u5e76\u5c06\u5176\u66ff\u6362\u4e3a\u4ee5\u4e0b\u5185\u5bb9\u3002<\/p>\n
      \u5217\u8868 8.16 \u66f4\u65b0\u4e86\u4e3b\u9875 Razor \u4ee3\u7801<\/p>\n
      <h1>City Breaks<\/h1>\n<div class="container">\n    <div class="row">\n\n        @foreach (var city in Model.Cities)                                  \u2776\n        {\n            <div class="col-4 p-3" style="text-shadow: rgb(0, 0, 0) 1px 1px \n             \u27a5 1px">\n                <div class="card p-3 shadow"                                 \u2777\n                \u27a5 style="background:url(\/images\/cities\/@city.Photo)         \u2777\n                \u27a5 no-repeat center;background-size: cover;height:240px;">   \u2777\n                    <h3>\n                        <a class="text-white text-decoration-none"           \u2778\n                        \u27a5 asp-page="\/City" asp-route-name="@city.Name">     \u2778\n                        \u27a5 @city.Name<\/a>                                    \u2778\n                       <img                                                  \u2779\n                       \u27a5 src="\/images\/flags\/@(city.Country.CountryCode).png"\u2779\n                       \u27a5 aria-label="@($"{city.Name},                       \u2779\n                       \u27a5 {city.Country.CountryName}")">                     \u2779\n                    <\/h3>\n                    <h6 class="text-white">                                  \u277a\n                     \u27a5 @city.Properties.Count()properties<\/h6>              \u277a\n                <\/div>\n            <\/div>\n        }\n    <\/div>\n<\/div><\/code><\/pre>\n
      \u2776 \u904d\u5386\u6240\u6709\u57ce\u5e02\u3002
      \n\u2777 \u4f7f\u7528\u6bcf\u4e2a\u57ce\u5e02\u7684 Photo \u5c5e\u6027\u8bbe\u7f6e\u80cc\u666f\u56fe\u50cf\u3002
      \n\u2778 \u8f93\u51fa\u57ce\u5e02\u7684\u540d\u79f0\u3002
      \n\u2779 \u5f15\u7528\u57ce\u5e02\u7684 Country \u5c5e\u6027\uff0c\u5e76\u4f7f\u7528\u5176 CountryCode \u5448\u73b0\u76f8\u5e94\u7684\u56fd\u65d7\u56fe\u6807\u3002
      \n\u277a \u4f7f\u7528 Count\uff08\uff09 \u65b9\u6cd5\u5448\u73b0\u4e0e\u6bcf\u4e2a\u57ce\u5e02\u5173\u8054\u7684\u5c5e\u6027\u603b\u6570\u3002<\/p>\n
      \u73b0\u5728\uff0c\u60a8\u53ea\u9700\u5c06 Program.cs \u4e2d\u73b0\u6709\u7684 SimpleCityService \u6ce8\u518c\u66ff\u6362\u4e3a\u6307\u5b9a\u65b0 CityService \u4f5c\u4e3a\u7528\u4e8e ICityService \u7684\u5b9e\u73b0\u7684\u6ce8\u518c\uff1a<\/p>\n
      builder.Services.AddScoped<ICityService, CityService>();<\/code><\/pre>\n
      \u5b8c\u6210\u6b64\u4f5c\u540e\uff0c\u60a8\u53ef\u4ee5\u8fd0\u884c\u5e94\u7528\u7a0b\u5e8f\u5e76\u4eab\u53d7\u65b0\u7684\u4e3b\u9875\uff08\u56fe 8.7\uff09<\/p>\n
      <\/p>\n
      \u56fe 8.7 \u4e3b\u9875\u663e\u793a\u6570\u636e\u5e93\u4e2d\u7684\u6570\u636e\u3002<\/p>\n
      \u5728\u7ee7\u7eed\u4e4b\u524d\uff0c\u8bf7\u5bfc\u822a\u5230 \/property-manager \/create \u4ee5\u786e\u4fdd\u5df2\u586b\u5145 select-city \u5217\u8868\u3002\u4ee5\u524d\uff0c\u8be5\u6570\u636e\u6765\u81ea SimpleCityService\uff0c\u73b0\u5728\u5b83\u6765\u81ea\u6570\u636e\u5e93\u3002\u60a8\u4e0d\u4ec5\u6709\u4e00\u4e2a\u8fde\u63a5\u5230\u5e94\u7528\u7a0b\u5e8f\u7684\u5de5\u4f5c\u6570\u636e\u5e93\uff0c\u800c\u4e14\u8fd8\u6709\u4e00\u4e2a\u5f88\u597d\u7684\u793a\u4f8b\uff0c\u8bf4\u660e\u677e\u6563\u8026\u5408\u5982\u4f55\u4f7f\u5e94\u7528\u7a0b\u5e8f\u80fd\u591f\u8f7b\u677e\u8fdb\u884c\u66f4\u6539\u3002\u60a8\u4e0d\u5fc5\u4fee\u6539 Create \u9875\u9762\u7684\u4efb\u4e00\u6587\u4ef6\u4e2d\u7684\u4ee3\u7801\u5373\u53ef\u4f7f\u5176\u4e0e\u6570\u636e\u5e93\u4e00\u8d77\u4f7f\u7528\u3002\u60a8\u6240\u8981\u505a\u7684\u5c31\u662f\u66f4\u6539\u670d\u52a1\u6ce8\u518c\u3002<\/p>\n
      8.3.2 \u9009\u62e9\u5355\u4e2a\u8bb0\u5f55<\/h3>\n
      \u73b0\u5728\uff0c\u60a8\u5df2\u7ecf\u6709\u4e86\u4e00\u4e2a\u9009\u62e9\u591a\u6761\u8bb0\u5f55\u7684\u826f\u597d\u5de5\u4f5c\u793a\u4f8b\uff0c\u60a8\u5c06\u4fee\u6539 City \u9875\u9762\uff0c\u4ee5\u6839\u636e URL \u4e2d\u4f20\u9012\u7684\u503c\u68c0\u7d22\u5355\u4e2a\u8bb0\u5f55\u3002\u9996\u5148\uff0c\u60a8\u9700\u8981\u66f4\u65b0 ICityService \u4ee5\u5305\u542b\u4e00\u4e2a\u540d\u4e3a GetByNameAsync \u7684\u65b0\u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u5c06\u5b57\u7b26\u4e32\u4f5c\u4e3a\u53c2\u6570\u5e76\u8fd4\u56de Task<City><\/code>\u3002<\/p>\n
      \u6e05\u5355 8.17 \u5411 ICityService \u6dfb\u52a0\u65b0\u65b9\u6cd5<\/p>\n
      public interface ICityService\n{\n    Task<List<City>> GetAllAsync();\n    Task<City> GetByNameAsync(string name);\n}<\/code><\/pre>\n
      \u60a8\u6709\u4e24\u4e2a\u670d\u52a1\u5b9e\u73b0\u6b64\u63a5\u53e3;\u60a8\u5c06\u4e0d\u4f1a\u518d\u6b21\u4f7f\u7528 SimpleCityService\uff0c\u56e0\u6b64\u60a8\u53ef\u4ee5\u5b89\u5168\u5730\u5220\u9664\u5b83\u6216\u4f7f\u7528 NotImplementedException \u4e3a\u6ee1\u8db3\u7f16\u8bd1\u5668\u63a5\u53e3\u7ea6\u5b9a\u7684\u65b9\u6cd5\u521b\u5efa\u4e00\u4e2a\u5b58\u6839\uff1a<\/p>\n
      public Task<City> GetByNameAsync(string name) => throw new \n NotImplementedException();<\/code><\/pre>\n
      \u5982\u679c\u60a8\u9009\u62e9\u91c7\u7528\u540e\u4e00\u79cd\u65b9\u5f0f\uff0c\u5219\u9700\u8981\u8bb0\u4f4f\u5bf9\u4ee5\u540e\u6dfb\u52a0\u5230 ICityService \u63a5\u53e3\u7684\u6240\u6709\u5176\u4ed6\u65b9\u6cd5\u6267\u884c\u76f8\u540c\u7684\u4f5c\u3002\u63a5\u4e0b\u6765\uff0c\u60a8\u5c06\u5728 CityService \u7c7b\u4e2d\u63d0\u4f9b\u4e00\u4e2a\u6709\u6548\u7684\u5b9e\u73b0\u3002<\/p>\n
      \u5217\u8868 8.18 \u4f7f\u7528\u540d\u79f0\u4f5c\u4e3a\u6761\u4ef6\u8fd4\u56de\u5355\u4e2a\u57ce\u5e02\u7684\u67e5\u8be2<\/p>\n
      public async Task<City> GetByNameAsync(string name)\n{\n    return await _context.Cities\n        .Include(c => c.Country)\n        .Include(c => c.Properties.Where(p => p.AvailableFrom < \n         \u27a5 DateTime.Now))\n        .SingleOrDefaultAsync(c => c.Name == name);\n}<\/code><\/pre>\n
      \u8be5\u67e5\u8be2\u4e0e\u524d\u4e00\u4e2a\u67e5\u8be2\u7684\u4e0d\u540c\u4e4b\u5904\u4ec5\u5728\u4e8e\u7528\u4e8e\u5bfc\u81f4\u6267\u884c\u7684\u65b9\u6cd5\u3002\u8fd9\u4e00\u6b21\uff0c\u60a8\u5c06\u4f7f\u7528 SingleOrDefaultAsync \u65b9\u6cd5\u3002\u6b64\u65b9\u6cd5\u671f\u671b\u6570\u636e\u5e93\u4e2d\u6709\u96f6\u4e2a\u6216\u4e00\u4e2a\u5339\u914d\u7684\u8bb0\u5f55\u3002\u5982\u679c\u6ca1\u6709\u5339\u914d\u7684\u8bb0\u5f55\uff0c\u8be5\u65b9\u6cd5\u5c06\u8fd4\u56de\u9ed8\u8ba4\u503c\uff0c\u5728\u672c\u4f8b\u4e2d\u4e3a null\u3002\u5982\u679c\u591a\u6761\u8bb0\u5f55\u4e0e\u6761\u4ef6\u5339\u914d\uff0c\u5219\u4f1a\u5f15\u53d1\u5f02\u5e38\u3002\u5982\u679c\u9884\u8ba1\u53ea\u6709\u4e00\u6761\u5339\u914d\u8bb0\u5f55\uff0c\u5219\u53ef\u4ee5\u4f7f\u7528 SingleAsync \u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u5728\u6ca1\u6709\u5339\u914d\u9879\u7684\u60c5\u51b5\u4e0b\u8fd4\u56de\u5f02\u5e38\u3002\u5982\u679c\u60a8\u8ba4\u4e3a\u53ef\u80fd\u6709\u591a\u4e2a\u8bb0\u5f55\u4e0e\u6761\u4ef6\u5339\u914d\uff0c\u5219\u5e94\u4f7f\u7528 FirstAsync \u6216 FirstOrDefaultAsync \u65b9\u6cd5\uff0c\u5177\u4f53\u53d6\u51b3\u4e8e\u662f\u5426\u6709\u53ef\u80fd\u6ca1\u6709\u5339\u914d\u9879\u3002\u8fd9\u5c06\u6839\u636e\u6570\u636e\u5e93\u7684\u9ed8\u8ba4\u987a\u5e8f\u6216\u901a\u8fc7 OrderBy \u65b9\u6cd5\u6307\u5b9a\u7684\u987a\u5e8f\u8fd4\u56de\u7b2c\u4e00\u4e2a\u5339\u914d\u9879\u3002\u4f8b\u5982\uff1a<\/p>\n
      return _context.Cities.OrderBy(c => c.Name).FirstAsync(c => c.Name == name);<\/code><\/pre>\n
      \u60a8\u5728\u6b64\u5904\u4f7f\u7528 SingleOrDefaultAsync \u65b9\u6cd5\uff0c\u56e0\u4e3a\u60a8\u65e0\u6cd5\u5b8c\u5168\u63a7\u5236\u4f20\u9012\u7ed9\u8be5\u65b9\u6cd5\u7684\u503c\u3002\u60a8\u53ef\u80fd\u8ba4\u4e3a\u8fd9\u6837\u505a\u662f\u56e0\u4e3a\u60a8\u7684\u4ee3\u7801\u4ece\u6765\u81ea\u6570\u636e\u5e93\u7684\u6570\u636e\u751f\u6210\u94fe\u63a5\u3002\u4f46\u662f\uff0c\u5f53\u60a8\u5c06\u8fd9\u4e9b\u6570\u636e\u4f5c\u4e3a URL \u7684\u4e00\u90e8\u5206\u5305\u542b\u5728\u5176\u4e2d\u65f6\uff0c\u60a8\u5c31\u662f\u5728\u5411\u5916\u754c\u516c\u5f00\u8be5\u6570\u636e\uff0c\u5e76\u4e14\u4e0d\u80fd\u76f8\u4fe1\u5b83\u4e0d\u4f1a\u88ab\u65e0\u8f9c\u6216\u5176\u4ed6\u65b9\u5f0f\u66f4\u6539\u3002\u63a5\u4e0b\u6765\uff0c\u60a8\u9700\u8981\u66f4\u6539 CityModel \u7c7b\u7684\u4ee3\u7801\uff0c\u56e0\u6b64\u5c06 \\Pages\\City.cshtml.cs \u7684\u5185\u5bb9\u66ff\u6362\u4e3a\u4ee5\u4e0b\u4ee3\u7801\u3002<\/p>\n
      Listing 8.19 \u4fee\u8ba2\u540e\u7684 CityModel \u4ee3\u7801<\/p>\n
      using CityBreaks.Models;\nusing CityBreaks.Services;\nusing Microsoft.AspNetCore.Mvc;\nusing Microsoft.AspNetCore.Mvc.RazorPages;\n\nnamespace CityBreaks.Pages;\n\npublic class CityModel : PageModel\n{\n    private readonly ICityService _cityService;\n    public CityModel(ICityService cityService)\n    {\n        _cityService = cityService;\n    }\n\n    [BindProperty(SupportsGet = true)]\n    public string Name { get; set; }\n    public City City { get; set; }\n\n    public async Task<IActionResult> OnGetAsync()\n    {\n        City = await _cityService.GetByNameAsync(Name);\n        if(City == null)\n        {\n            return NotFound();\n        }\n        return Page();\n    }\n}<\/code><\/pre>\n
      \u60a8\u6ce8\u5165 ICityService \u5e76\u4f7f\u7528\u5b83\u6765\u68c0\u7d22\u4e0e\u4f20\u9012\u7ed9 URL \u4e2d\u7684\u9875\u9762\u7684\u540d\u79f0\u5339\u914d\u7684\u57ce\u5e02\u3002\u60a8\u5e94\u8be5\u9884\u6599\u5230\u7ed3\u679c\u53ef\u80fd\u4e3a null\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u60a8\u5c06\u8ba9\u7528\u6237\u77e5\u9053\u6ca1\u6709\u5339\u914d\u7684\u9875\u9762\u3002\u73b0\u5728\u5269\u4e0b\u7684\u5c31\u662f\u663e\u793a\u5339\u914d\u8bb0\u5f55\u7684\u8be6\u7ec6\u4fe1\u606f\uff08\u5982\u679c\u627e\u5230\uff09\u3002<\/p>\n
      \u4e3a\u4e86\u7ed9\u7ec6\u8282\u589e\u52a0\u4e00\u4e9b\u89c6\u89c9\u8da3\u5473\uff0c\u4f60\u5c06\u52a0\u5165\u4e00\u4e9b\u6765\u81ea Font Awesome \uff08https:\/\/fontawesome.com<\/a>\uff09 \u7684\u514d\u8d39\u56fe\u6807\u3002\u60a8\u9700\u8981\u5728 Pages\\Shared \\ _Layout.cshtml \u6587\u4ef6\u4e2d\u6dfb\u52a0\u6307\u5411\u5176\u56fe\u6807\u7684 CDN \u7248\u672c\u7684\u94fe\u63a5\u3002\u5728\u7ed3\u675f <\/head><\/code> \u6807\u8bb0\u4e4b\u524d\u6dfb\u52a0\u4ee5\u4e0b\u4ee3\u7801\u884c\uff1a<\/p>\n
      <link rel="stylesheet" href="https:\/\/cdnjs.cloudflare.com\/ajax\/libs\/font-awesome\/5.15.4\/css\/all.min.css" \/><\/code><\/pre>\n
      \u73b0\u5728\uff0c\u5c06 Pages\\City.cshtml \u6587\u4ef6\u7684\u5185\u5bb9\u66f4\u6539\u4e3a\u4ee5\u4e0b\u5185\u5bb9\u3002<\/p>\n
      Listing 8.20 \u6e32\u67d3\u6307\u5b9a City \u7684\u7ec6\u8282<\/p>\n
      @page "{name}"\n@model CityBreaks.Pages.CityModel\n@{\n    ViewData["Title"] = $"{Model.City.Name} Details";\n}\n<h3>@Model.City.Name<\/h3>\n@foreach (var property in Model.City.Properties)\n{\n    <div class="mb-3">\n        <h5>@property.Name<\/h5>\n        <p class="mb-1">@property.Address<\/p>\n        <i class="fas fa-euro-sign text-muted"><\/i> \n        \u27a5 @property.DayRate.ToString("F2")<br>\n        @if (!property.SmokingPermitted)\n        {\n            <i class="fas fa-smoking-ban text-danger"><\/i>\n        }\n        @for (var i = 1; i <= property.MaxNumberOfGuests; i++)\n        {\n            <i class="fas fa-bed text-info"><\/i>\n        }\n    <\/div>\n}<\/code><\/pre>\n
      \u8be5\u4ee3\u7801\u904d\u5386\u57ce\u5e02\u4e2d\u6240\u6709\u53ef\u7528\u7684\u5c5e\u6027\u5e76\u5448\u73b0\u5176\u8be6\u7ec6\u4fe1\u606f\uff0c\u4f7f\u7528 Font Awesome \u56fe\u6807\u663e\u793a\u7981\u6b62\u5438\u70df\u6807\u5fd7\uff08\u5982\u679c\u4e0d\u5141\u8bb8\u5438\u70df\uff09\uff0c\u5e76\u4f7f\u7528\u591a\u4e2a\u5e8a\u56fe\u6807\u8868\u793a\u5141\u8bb8\u7684\u6700\u591a\u5ba2\u4eba\u6570\u3002\u60a8\u8fd8\u4f7f\u7528\u4e86\u6b27\u5143\u56fe\u6807\u6765\u8868\u793a\u8d27\u5e01\u3002\u60a8\u73b0\u5728\u6240\u8981\u505a\u7684\u5c31\u662f\u542f\u52a8\u5e94\u7528\u7a0b\u5e8f\u5e76\u5355\u51fb\u4e3b\u9875\u4e0a\u7684\u4e00\u4e2a\u57ce\u5e02\uff08\u56fe 8.8\uff09\u3002<\/p>\n
      <\/p>\n
      \u56fe 8.8 City\uff08\u57ce\u5e02\uff09\u9875\u9762\u8fd4\u56de 404 Not Found\uff08\u672a\u627e\u5230\uff09\u3002<\/p>\n
      \u54e6\uff01\u90a3\u91cc\u53d1\u751f\u4e86\u4ec0\u4e48\uff1f\u597d\u5427\uff0c\u5982\u679c\u60a8\u4f7f\u7528\u7684\u662f SQL Server \u800c\u4e0d\u662f SQLite\uff0c\u5219\u5f88\u53ef\u80fd\u53ef\u4ee5\u770b\u5230\u6240\u9009\u57ce\u5e02\u7684\u8be6\u7ec6\u4fe1\u606f\u3002SQLite \u7684\u95ee\u9898\u5728\u4e8e\uff0c\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u5b57\u7b26\u4e32\u6bd4\u8f83\u533a\u5206\u5927\u5c0f\u5199\u3002\u60a8\u5c06\u4e00\u4e2a\u5c0f\u5199\u503c\u4ece URL \u4f20\u9012\u7ed9 service \u65b9\u6cd5\uff0c\u540e\u8005\u5c06\u5176\u4e0e\u6570\u636e\u5e93\u4e2d\u7684\u6df7\u5408\u5927\u5c0f\u5199\u503c\u8fdb\u884c\u6bd4\u8f83\u3002\u8981\u89e3\u51b3\u6b64\u95ee\u9898\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 EF.Functions.Collate \u65b9\u6cd5\u6765\u6307\u5b9a SQLite \u5e94\u8be5\u7528\u4e8e\u6b64\u6bd4\u8f83\u7684\u6392\u5e8f\u89c4\u5219\u3002\u82f1 \u5b5a\u3002\u51fd\u6570\u5305\u542b\u4e00\u7ec4\u6709\u7528\u7684\u65b9\u6cd5\uff0c\u8fd9\u4e9b\u65b9\u6cd5\u53ef\u8f6c\u6362\u4e3a\u6570\u636e\u5e93\u51fd\u6570\uff0c\u5e76\u4e14\u4ec5\u9002\u7528\u4e8e EF Core \u4e2d\u4f7f\u7528\u7684 LINQ \u67e5\u8be2\u3002\u8be5\u6587\u6863\u63d0\u4f9b\u4e86\u5b83\u4eec\u7684\u5b8c\u6574\u5217\u8868 \uff08http:\/\/mng.bz\/gRrv\uff09\u3002\u6253\u5f00<\/a> CityService\uff0c\u5e76\u66f4\u6539 GetByNameAsync \u65b9\u6cd5\uff0c\u5982\u4e0b\u6240\u793a\u3002<\/p>\n
      Listing 8.21 \u6307\u5b9a\u8981\u7528\u4e8e\u67e5\u8be2\u7684\u6392\u5e8f\u89c4\u5219<\/p>\n
      public async Task<City> GetByNameAsync(string name)\n{\n    name = name.Replace("-"," ");                             \u2776\n    return await _context.Cities\n        .Include(c => c.Country)\n        .Include(c => c.Properties.Where(p => \n        \u27a5 p.AvailableFrom < DateTime.Now))\n        .SingleOrDefaultAsync(c => \n        \u27a5 EF.Functions.Collate(c.Name, "NOCASE") == name);   \u2777\n}<\/code><\/pre>\n
      \u2776 \u5c06\u9875\u9762\u8def\u7531\u53c2\u6570 transformer \u6dfb\u52a0\u7684\u8fde\u5b57\u7b26\u66ff\u6362\u4e3a\u7a7a\u683c\uff0c\u4ee5\u4fbf\u5b83\u4eec\u4e0e\u6570\u636e\u5e93\u6761\u76ee\u5339\u914d\u3002
      \n\u2777 \u4f7f\u7528 EF\u3002Functions.Collate \u4e3a SQLite \u6307\u5b9a NOCASE \u7684\u6392\u5e8f\u89c4\u5219\u3002<\/p>\n
      \u5b8c\u6210\u6b64\u6821\u6b63\u540e\uff0c\u60a8\u5e94\u8be5\u80fd\u591f\u67e5\u770b\u6240\u9009\u57ce\u5e02\u7684\u8be6\u7ec6\u4fe1\u606f\uff08\u56fe 8.9\uff09\u3002<\/p>\n
      <\/p>\n
      \u56fe 8.9 \u663e\u793a\u6240\u9009\u57ce\u5e02\u7684\u8be6\u7ec6\u4fe1\u606f\u3002<\/p>\n
      \u4f1f\u5927\uff01\u6b64\u65f6\uff0c\u60a8\u5df2\u7ecf\u68c0\u7d22\u4e86\u6570\u636e\u7684\u5355\u4e2a\u5b9e\u4f8b\u4ee5\u53ca\u96c6\u5408\u3002\u60a8\u8fd8\u68c0\u7d22\u4e86\u76f8\u5173\u6570\u636e\u3002\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5c06\u4e13\u6ce8\u4e8e CRUD \u7684\u5176\u4ed6\u65b9\u9762\uff1a\u521b\u5efa\u65b0\u8bb0\u5f55\u3001\u66f4\u65b0\u8bb0\u5f55\u548c\u5220\u9664\u8bb0\u5f55\u3002\u540c\u65f6\uff0c\u6211\u4eec\u5c06\u7814\u7a76\u53e6\u4e00\u4e2a\u53ef\u4ee5\u52a0\u5feb\u8fd9\u4e9b\u793a\u4f8b\u5f00\u53d1\u7684\u529f\u80fd\uff1a\u811a\u624b\u67b6\u3002<\/p>\n
      8.4 \u811a\u624b\u67b6 CRUD \u9875\u9762<\/h3>\n
      \u57fa\u67b6\u662f\u4e00\u79cd\u7528\u4e8e\u5728\u8bbe\u8ba1\u65f6\u751f\u6210\u4ee3\u7801\u7684\u6280\u672f\uff0c\u7528\u4e8e\u5728\u4f7f\u7528 EF Core \u65f6\u652f\u6301\u591a\u79cd\u5e38\u89c1\u7684\u5e94\u7528\u7a0b\u5e8f\u65b9\u6848\u3002\u57fa\u67b6\u5de5\u5177\u652f\u6301\u4f7f\u7528\u8868 8.1 \u4e2d\u7684\u6a21\u677f\u751f\u6210\u4e0e\u6570\u636e\u5e93\u4ea4\u4e92\u7684 Razor \u9875\u9762\u3002<\/p>\n
      \u8868 8.1 \u57fa\u67b6\u5de5\u5177\u53ef\u7528\u7684\u6a21\u677f<\/p>\n\n\n\n\n<\/colgroup>\n\n\n\n\n\n\n\n
      \n
      <\/a>Template<\/p>\n<\/th>\n
      		\n
      <\/a>Description<\/p>\n<\/th>\n<\/tr>\n
      \n
      <\/a>Create<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Generates a Razor page with a form for creating the specified model class and PageModel<\/span> handlers complete with code for saving to a database<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>Edit<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Generates a Razor page with a form for editing the specified model class and PageModel<\/span> handlers complete with code for retrieving the specified entity and saving changes to a database<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>Delete<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Produces a page that displays details of the selected entity and a form with a hidden field that passes the key value of the entity to a handler method that removes it from the database<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>Details<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Produces a page that displays details of the selected entity<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>List<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Produces a page that displays details of all instances of the selected entity in a table<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
      \u6b64\u5916\uff0c\u57fa\u67b6\u5de5\u5177\u652f\u6301\u7a7a\u6a21\u677f\uff0c\u8fd9\u76f8\u5f53\u4e8e\u6bcf\u6b21\u4ece Visual Studio \u5bf9\u8bdd\u6846\u6216\u547d\u4ee4\u884c\u5411\u5e94\u7528\u7a0b\u5e8f\u6dfb\u52a0\u65b0\u7684 Razor \u9875\u9762\u65f6\u6240\u770b\u5230\u7684\u6a21\u677f\u3002\u57fa\u67b6\u5de5\u5177\u751f\u6210\u7684\u4ee3\u7801\u5f88\u5c11\u53ef\u7528\u4e8e\u751f\u4ea7\u3002\u5b83\u4ec5\u63d0\u4f9b\u4e00\u4e2a\u8d77\u70b9\u3002\u60a8\u5c06\u4f7f\u7528\u8be5\u5de5\u5177\u4e3a Property \u7c7b\u751f\u6210\u6240\u6709 CRUD \u9875\u9762\uff0c\u7136\u540e\u67e5\u770b\u751f\u6210\u7684\u4ee3\u7801\u4ee5\u4e86\u89e3\u5176\u7f3a\u70b9\u4ee5\u53ca\u60a8\u9700\u8981\u91c7\u53d6\u54ea\u4e9b\u63aa\u65bd\u6765\u89e3\u51b3\u4efb\u4f55\u95ee\u9898\u3002<\/p>\n
      \u5728\u4f7f\u7528\u57fa\u67b6\u5de5\u5177\u4e4b\u524d\uff0c\u5fc5\u987b\u5b89\u88c5\u5305\u542b\u6a21\u677f\u7684 NuGet \u5305\uff1aMicrosoft.VisualStudio.Web.CodeGeneration.Design\u3002\u5982\u679c\u60a8\u4f7f\u7528\u7684\u662f Visual Studio\uff0c\u5219\u5f53\u60a8\u4f7f\u7528\u57fa\u67b6\u65f6\uff0cIDE \u5c06\u5c1d\u8bd5\u6dfb\u52a0\u5bf9\u6b64\u5305\u7684\u6700\u65b0\u7a33\u5b9a\u7248\u672c\u7684\u5f15\u7528\u3002\u4f46\u662f\uff0c\u6839\u636e\u6211\u7684\u7ecf\u9a8c\uff0cVisual Studio \u5728\u5b89\u88c5\u5305\u540e\u4f1a\u62a5\u544a\u4e00\u4e2a\u9519\u8bef\uff0c\u8981\u6c42\u60a8\u518d\u6b21\u6307\u5b9a\u57fa\u67b6\u9009\u62e9\u3002\u56e0\u6b64\uff0c\u6211\u901a\u5e38\u4f1a\u624b\u52a8\u6dfb\u52a0\u5305\u5f15\u7528\u3002\u5047\u8bbe\u60a8\u8981\u4f7f\u7528\u547d\u4ee4\u884c\u8fdb\u884c\u57fa\u67b6\u3002\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u60a8\u4ecd\u7136\u9700\u8981\u4f7f\u7528\u6211\u4eec\u5df2\u7ecf\u4ecb\u7ecd\u7684\u7528\u4e8e\u7ba1\u7406 NuGet \u7684\u4efb\u4f55\u53ef\u7528\u65b9\u6cd5\u624b\u52a8\u6dfb\u52a0\u5305\u3002<\/p>\n
      8.4.1 Visual Studio \u57fa\u67b6\u8bf4\u660e<\/h3>\n
      \u57fa\u67b6\u5185\u7f6e\u4e8e Visual Studio \u4e2d\uff0c\u53ef\u4ece Add \uff08\u6dfb\u52a0\uff09 \u5bf9\u8bdd\u6846\u8bbf\u95ee\u3002\u53f3\u952e\u5355\u51fb Pages\\PropertyManager \u6587\u4ef6\u5939\uff0c\u7136\u540e\u4ece\u5173\u8054\u83dc\u5355\u4e2d\u9009\u62e9\u6dfb\u52a0\u3002\u7136\u540e\u9009\u62e9 New Scaffolded Item...\u4ece\u7b2c\u4e8c\u4e2a\u83dc\u5355\u7ec4\u3002\u4ece\u51fa\u73b0\u7684\u5bf9\u8bdd\u6846\u4e2d\u9009\u62e9 Razor Pages\uff0c\u7136\u540e\u9009\u62e9 Razor Pages using Entity Framework \uff08CRUD\uff09\u3002\u63a5\u4e0b\u6765\uff0c\u5355\u51fb Add \u6309\u94ae\u3002\u5728\u4e0b\u4e00\u4e2a\u5bf9\u8bdd\u6846\u4e2d\uff0c\u9009\u62e9 Property \uff08CityBreaks.Models\uff09 \u4f5c\u4e3a Model \u7c7b\uff0c\u5e76\u9009\u62e9 CityBreaksContext \u4f5c\u4e3a Data \u4e0a\u4e0b\u6587\u7c7b\u3002\u5c06\u5176\u4ed6\u9009\u9879\u4fdd\u7559\u4e3a\u9ed8\u8ba4\u503c;\u4e5f\u5c31\u662f\u8bf4\uff0cReference Script Libraries \u548c Use a Layout Page \u90fd\u5e94\u8be5\u88ab\u9009\u4e2d\u3002\u5c06\u5e03\u5c40\u9875\u9762\u8f93\u5165\u7559\u7a7a\u3002\u53c2\u89c1\u56fe 8.10\u3002<\/p>\n
      <\/p>\n
      \u56fe 8.10 Visual Studio \u4e2d\u7684\u57fa\u67b6\u5bf9\u8bdd\u6846<\/p>\n
      \u5355\u51fb Add \u6309\u94ae\u3002\u7cfb\u7edf\u5c06\u63d0\u793a\u60a8\u66ff\u6362\u4e0e Create \u9875\u9762\u76f8\u5173\u7684\u73b0\u6709\u6587\u4ef6\u3002\u5355\u51fb Yes \uff08\u662f\uff09\u3002\u7136\u540e\uff0c\u4ee3\u7801\u751f\u6210\u5668\u5e94\u8fd0\u884c\u3002\u60a8\u53ef\u80fd\u4f1a\u53d1\u73b0\uff0c\u57fa\u67b6\u5de5\u5177\u6dfb\u52a0\u4e86\u5bf9 Microsoft.EntityFrameworkCore.SqlServer \u5305\u7684\u5f15\u7528\u3002\u5728\u4f7f\u7528 SQLite \u6570\u636e\u5e93\u65f6\uff0c\u60a8\u7684\u5e94\u7528\u7a0b\u5e8f\u4e0d\u9700\u8981\u8fd9\u6837\u505a;\u53ea\u6709\u57fa\u67b6\u5de5\u5177\u9700\u8981\u5b83\u3002\u5b8c\u6210\u57fa\u67b6\u540e\uff0c\u60a8\u53ef\u4ee5\u6839\u636e\u9700\u8981\u5220\u9664\u6b64\u5f15\u7528\u3002\u5982\u679c\u4f7f\u7528\u7684\u662f SQL Server\uff0c\u5219\u6b64\u5f15\u7528\u5df2\u5b58\u5728\uff0c\u5e76\u4e14\u5e94\u7528\u7a0b\u5e8f\u9700\u8981\u6b64\u5f15\u7528\u3002<\/p>\n
      8.4.2 \u4ece\u547d\u4ee4\u884c\u642d\u5efa\u57fa\u67b6<\/h3>\n
      \u82e5\u8981\u4ece\u547d\u4ee4\u884c\u642d\u5efa\u9879\uff0c\u5fc5\u987b\u5148\u5b89\u88c5 dotnet-aspnet-codegenerator \u5de5\u5177\u3002\u8fd9\u662f\u4e00\u4e2a\u5168\u5c40\u5de5\u5177\uff0c\u7c7b\u4f3c\u4e8e\u60a8\u4e4b\u524d\u5b89\u88c5\u7684 dotnet-ef \u5de5\u5177\u3002\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u5b89\u88c5\u8be5\u5de5\u5177\uff1a<\/p>\n
      dotnet tool install --global dotnet-aspnet-codegenerator<\/code><\/pre>\n
      \u5b89\u88c5\u8be5\u5de5\u5177\u540e\uff0c\u60a8\u5c31\u53ef\u4ee5\u4f7f\u7528\u5b83\u4e86\u3002\u547d\u4ee4\u540d\u79f0\u4e0e\u5de5\u5177\u76f8\u540c\uff1adotnet-aspnet-codegenerator\u3002\u8be5\u547d\u4ee4\u9700\u8981\u60a8\u8981\u4f7f\u7528\u7684\u751f\u6210\u5668\u7684\u540d\u79f0\uff0c\u540e\u8ddf\u60a8\u8981\u5e94\u7528\u7684\u9009\u9879\u3002Razor Pages \u751f\u6210\u5668\u7684\u540d\u79f0\u662f razorpage\u3002\u8868 8.2 \u4e2d\u8be6\u7ec6\u4ecb\u7ecd\u4e86 Razor Pages \u751f\u6210\u5668\u9009\u9879\u3002<\/p>\n
      \u8868 8.2 Razor Pages \u751f\u6210\u5668\u9009\u9879<\/p>\n\n\n\n\n<\/colgroup>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
      \n
      <\/a>Option<\/p>\n<\/th>\n
      		\n
      <\/a>Description<\/p>\n<\/th>\n<\/tr>\n
      \n
      <\/a>--model|-m<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Model class to use<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--dataContext|-dc<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>DbContext<\/span> class to use<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--referenceScriptLibraries|-scripts<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Switch to specify whether to reference script libraries in the generated views<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--layout|-l<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Custom layout page to use<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--useDefaultLayout|-udl<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Switch to specify that the default layout should be used for the views<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--force|-f<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Overwrites existing files<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--relativeFolderPath|-outDir<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Specifies the relative output folder path from project where the file needs to be generated; if not specified, the file will be generated in the project folder<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--namespaceName|-namespace<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Specifies the name of the namespace to use for the generated PageModel<\/span><\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--partialView|-partial<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Generates a partial view; other layout options (-l<\/span> and -udl<\/span>) are ignored if this is specified<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--noPageModel|-npm<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Switch to prevent generating a PageModel<\/span> class for an empty template<\/p>\n<\/td>\n<\/tr>\n
      \n
      <\/a>--useSqlite|-sqlite<\/span><\/a><\/p>\n<\/td>\n
      		\n
      <\/a>Flag to specify if DbContext<\/span> should use SQLite instead of SQL Server<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
      \u60a8\u53ef\u4ee5\u901a\u8fc7\u6307\u5b9a Razor \u9875\u9762\u7684\u540d\u79f0\u4ee5\u53ca\u8981\u4f7f\u7528\u7684\u6a21\u677f\u7684\u540d\u79f0\uff08\u4ee5\u4e0b\u9009\u9879\u4e4b\u4e00\uff09\u6765\u57fa\u4e8e\u73b0\u6709\u6a21\u677f\u642d\u5efa\u5404\u4e2a\u9875\u9762\u7684\u57fa\u67b6\uff1aEmpty\u3001Create\u3001Edit\u3001Delete\u3001Details \u6216 List\u3002\u6216\u8005\u4f60\u53ef\u4ee5\u7701\u7565 name \u548c template;\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u751f\u6210\u5668\u5c06\u642d\u5efa\u9664 empty template \u4e4b\u5916\u7684\u6240\u6709 Template\u3002<\/p>\n
      \u60a8\u5e0c\u671b\u4e3a Property \u7c7b\u642d\u5efa\u6240\u6709 CRUD \u9875\u9762\u7684\u57fa\u67b6\uff0c\u5e76\u4e14\u5e0c\u671b\u4f7f\u7528 CityBreaksContext \u4f5c\u4e3a\u6570\u636e\u4e0a\u4e0b\u6587\u3002\u60a8\u8fd8\u5e0c\u671b\u751f\u6210\u7684\u6587\u4ef6\u88ab\u653e\u7f6e\u5728 Pages\\PropertyManager \u6587\u4ef6\u5939\u4e2d\uff0c\u5e76\u4e14\u60a8\u5e0c\u671b\u5b83\u4eec\u4f7f\u7528\u8be5\u6587\u4ef6\u5939\u7684\u9ed8\u8ba4\u5e03\u5c40\u9875\u9762\u3002\u60a8\u4e0d\u4f1a\u4e3a\u9875\u9762\u6307\u5b9a\u547d\u540d\u7a7a\u95f4;\u76f8\u53cd\uff0c\u811a\u624b\u67b6\u5c06\u6839\u636e\u9879\u76ee\u540d\u79f0\u548c\u6587\u4ef6\u5939\u8def\u5f84\u751f\u6210\u4e00\u4e2a\uff1aCityBreaks.Pages.PropertyManager\u3002\u60a8\u5e0c\u671b\u5305\u542b\u4e0d\u663e\u773c\u7684\u9a8c\u8bc1\u811a\u672c\uff0c\u5e76\u4e14\u5e0c\u671b\u6307\u5b9a\u4e0a\u4e0b\u6587\u4f7f\u7528 SQLite\u3002\u5c06\u6240\u6709\u8fd9\u4e9b\u653e\u5728\u4e00\u8d77\uff0c\u60a8\u7684\u547d\u4ee4\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
      dotnet aspnet-codegenerator razorpage -m Property\n -dc CityBreaksContext -outDir\n Pages\\PropertyManager -udl -scripts -sqlite<\/code><\/pre>\n
      \u6b64\u547d\u4ee4\u5fc5\u987b\u5728\u5305\u542b\u9879\u76ee\u6587\u4ef6\u7684\u6587\u4ef6\u5939\u4e2d\u6267\u884c\u3002\u5b8c\u6210\u540e\uff0c\u9875\u9762\u5c06\u663e\u793a\u5728\u56fe 8.11 \u6240\u793a\u7684\u6307\u5b9a\u6587\u4ef6\u5939\u4e2d\u3002<\/p>\n
      <\/p>\n
      \u56fe 8.11 \u57fa\u67b6\u5f0f CRUD \u9875\u9762<\/p>\n
      8.4.3 \u4f7f\u7528\u57fa\u67b6\u9875
      \n\u65e0\u8bba\u60a8\u91c7\u7528\u54ea\u79cd\u65b9\u6cd5\u6765\u642d\u5efa CRUD \u9875\u9762\u7684\u57fa\u67b6\uff0c\u60a8\u73b0\u5728\u90fd\u5e94\u8be5\u5f97\u5230\u76f8\u540c\u7684\u7ed3\u679c\u3002\u60a8\u53ef\u80fd\u4f1a\u6ce8\u610f\u5230\u7684\u7b2c\u4e00\u4ef6\u4e8b\u662f\u5b83\u4eec\u65e0\u6cd5\u6784\u5efa\u3002\u5728\u64b0\u5199\u672c\u6587\u65f6\uff0c\u57fa\u67b6\u5de5\u5177\u4e2d\u5b58\u5728\u4e00\u4e2a\u9519\u8bef\uff0c\u8be5\u9519\u8bef\u5bfc\u81f4 @ \u5b57\u7b26\uff08\u4e0d\u80fd\u7528\u4f5c\u6709\u6548\u7684 C# \u6807\u8bc6\u7b26\uff09\u4f5c\u4e3a\u53c2\u6570\u5e94\u7528\u4e8e Edit\u3001Delete\u3001Details \u548c Index PageModel \u7c7b\u7684 Include \u65b9\u6cd5\u4e2d\uff1a<\/p>\n
      Property = await _context.Properties\n    .Include(@ => @.City).FirstOrDefaultAsync(m => m.Id == id);<\/code><\/pre>\n
      \u8fd9\u9700\u8981\u66ff\u6362\u4e3a\u53e6\u4e00\u4e2a\u5b57\u7b26 \u2014 \u6bd4\u5982 p\uff1a<\/p>\n
      Property = await _context.Properties\n    .Include(p => p.City).FirstOrDefaultAsync(m => m.Id == id);<\/code><\/pre>\n
      \u5b8c\u6210\u8be5\u66f4\u6539\u540e\uff0c\u60a8\u53ef\u4ee5\u68c0\u67e5\u5404\u4e2a\u9875\u9762\u4e2d\u7684\u4ee3\u7801\u5e76\u5bfb\u6c42\u6539\u8fdb\u5b83\u3002\u5728\u672c\u7ae0\u4e2d\uff0c\u6211\u5c06\u91cd\u70b9\u4ecb\u7ecd Edit \uff08\u7f16\u8f91\uff09 \u9875\u9762\u7684\u6587\u4ef6\u3002\u4e00\u65e6\u60a8\u4e86\u89e3\u4e86\u6b64\u9875\u9762\u4e2d\u9700\u8981\u89e3\u51b3\u7684\u95ee\u9898\u8303\u56f4\uff0c\u60a8\u5c31\u53ef\u4ee5\u5f88\u597d\u5730\u5bf9\u5176\u4ed6\u9875\u9762\u8fdb\u884c\u9002\u5f53\u7684\u66f4\u6539\u3002<\/p>\n
      \u9996\u5148\uff0c\u6211\u5c06\u5c55\u793a EditModel \u4ee3\u7801\u7684\u524d\u51e0\u884c\u3002\u60a8\u5c06\u6ce8\u610f\u5230\u7684\u7b2c\u4e00\u4ef6\u4e8b\u662f EditModel \u4f9d\u8d56\u4e8e EF Core \u4e0a\u4e0b\u6587\u3002<\/p>\n
      \u6e05\u5355 8.22 \u811a\u624b\u67b6 EditModel \u6784\u9020\u51fd\u6570<\/p>\n
      private readonly CityBreaks.Data.CityBreaksContext _context;\n\npublic EditModel(CityBreaks.Data.CityBreaksContext context)\n{\n    _context = context;\n}<\/code><\/pre>\n
      \u53c2\u8003\u4e0a\u4e00\u7ae0\uff0c\u8fd9\u8fdd\u53cd\u4e86\u4f9d\u8d56\u5012\u7f6e\u539f\u5219\uff0c\u56e0\u4e3a\u4e0a\u4e0b\u6587\u4e0d\u662f\u62bd\u8c61\u7684\u3002\u60a8\u7684 PageModel \u7c7b\u4e0e\u60a8\u9009\u62e9\u7684\u6570\u636e\u8bbf\u95ee\u6280\u672f\u7d27\u5bc6\u8026\u5408\uff0c\u4f8b\u5982\uff0c\u5982\u679c\u60a8\u5728\u5355\u5143\u6d4b\u8bd5\u4e2d\u5b9e\u4f8b\u5316\u6b64\u7c7b\u7684\u5b9e\u4f8b\uff0c\u5b83\u5c06\u8c03\u7528\u4e0a\u4e0b\u6587\u7684\u8fde\u63a5\u5b57\u7b26\u4e32\u4e2d\u5b9a\u4e49\u7684\u4efb\u4f55\u6570\u636e\u5e93\u3002\u8fd9\u4e0d\u662f\u5355\u5143\u6d4b\u8bd5\u3002\u8fd9\u662f\u4e00\u4e2a\u96c6\u6210\u6d4b\u8bd5\u3002\u7406\u60f3\u60c5\u51b5\u4e0b\uff0c\u60a8\u5e94\u8be5\u5c06\u4e0a\u4e0b\u6587\u66ff\u6362\u4e3a\u670d\u52a1\uff0c\u6216\u8005\u66f4\u786e\u5207\u5730\u8bf4\uff0c\u5c06\u5176\u62bd\u8c61\u66ff\u6362\u4e3a\u670d\u52a1\u3002<\/p>\n
      \u751f\u6210\u7684\u4ee3\u7801\u7684\u4e0b\u4e00\u4e2a\u4e3b\u8981\u95ee\u9898\u4f1a\u6253\u5f00\u4e00\u4e2a\u6f5c\u5728\u7684\u653b\u51fb\u5a92\u4ecb\u3002\u751f\u6210\u7684\u4ee3\u7801\u4f7f\u6574\u4e2a Property \u7c7b\u6210\u4e3a\u7ed1\u5b9a\u76ee\u6807\uff1a<\/p>\n
      [BindProperty]\npublic Property Property { get; set; }<\/code><\/pre>\n
      \u5982\u679c\u60a8\u56de\u60f3\u4e00\u4e0b\u7b2c 5 \u7ae0\uff0c\u60a8\u5e94\u8be5\u5c06\u9875\u9762\u4e0a\u7684\u7ed1\u5b9a\u76ee\u6807\u7684\u8303\u56f4\u9650\u5236\u4e3a\u4ec5\u60a8\u5e0c\u671b\u7528\u6237\u8bbe\u7f6e\u7684\u90a3\u4e9b\u5c5e\u6027\u3002\u5982\u679c\u516c\u5f00\u66f4\u591a\uff0c\u5219\u5e94\u7528\u7a0b\u5e8f\u5bb9\u6613\u53d7\u5230\u8fc7\u5ea6\u53d1\u5e03\u653b\u51fb\u3002\u60a8\u786e\u5b9e\u5e0c\u671b\u5c06 Property \u7c7b\u7684\u6240\u6709\u5f53\u524d\u5c5e\u6027\u516c\u5f00\u7ed9\u6a21\u578b\u7ed1\u5b9a\u5668\uff0c\u4f46\u60c5\u51b5\u53ef\u80fd\u5e76\u975e\u603b\u662f\u5982\u6b64\u3002\u5c06\u6765\uff0c\u60a8\u53ef\u80fd\u4f1a\u5411\u7c7b\u6dfb\u52a0\u66f4\u591a\u5c5e\u6027\u3002\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u5b83\u4eec\u5c06\u516c\u5f00\u7ed9\u6a21\u578b\u7ed1\u5b9a\uff0c\u56e0\u4e3a\u60a8\u4f7f\u7528 BindProperty \u5c5e\u6027\u4fee\u9970\u4e86\u6574\u4e2a\u7c7b\u3002\u56e0\u6b64\uff0c\u4f5c\u4e3a\u6700\u4f73\u5b9e\u8df5\uff0c\u60a8\u5e94\u8be5\u9996\u5148\u5355\u72ec\u6216\u901a\u8fc7 InputModel \u663e\u5f0f\u516c\u5f00\u5c5e\u6027\u3002\u4e0b\u4e00\u4e2a\u6e05\u5355\u663e\u793a\u4e86\u57fa\u67b6 OnGetAsync \u5904\u7406\u7a0b\u5e8f\u65b9\u6cd5\u3002<\/p>\n
      \u6e05\u5355 8.23 \u811a\u624b\u67b6 EditModel OnGetAsync \u5904\u7406\u7a0b\u5e8f<\/p>\n
      public async Task<IActionResult> OnGetAsync(int? id)\n{\n    if (id == null)\n    {\n        return NotFound();\n    } \n\n    Property = await _context.Properties\n        .Include(p => p.City).FirstOrDefaultAsync(m => m.Id == id);\n\n    if (Property == null)\n    {\n        return NotFound();\n    }\n    ViewData["CityId"] = new SelectList(_context.Cities, "Id", "Id");\n    return Page();\n}<\/code><\/pre>\n
      \u6211\u4e0d\u559c\u6b22\u65e0\u7528\u7684\u4ee3\u7801\uff0c\u6b64\u5904\u7406\u7a0b\u5e8f\u7684\u5f00\u5934\u6709\u4e00\u4e2a\u5f88\u597d\u7684\u793a\u4f8b\u3002\u8be5\u65b9\u6cd5\u91c7\u7528\u4e00\u4e2a\u53ef\u4e3a null \u7684\u53c2\u6570\uff0c\u8be5\u53c2\u6570\u8868\u793a\u8981\u7f16\u8f91\u7684\u9879\u7684\u6807\u8bc6\u3002\u7136\u540e\uff0c\u4e00\u4e2a\u4ee3\u7801\u5757\u68c0\u67e5\u662f\u5426\u4f20\u9012\u4e86\u503c\uff0c\u5982\u679c\u6ca1\u6709\uff0c\u5219\u8fd4\u56de 404\u3002\u60a8\u6709\u4e00\u79cd\u673a\u5236\uff0c\u53ef\u4ee5\u786e\u4fdd\u53ea\u6709\u5728\u63d0\u4f9b\u53f7\u7801\u65f6\u624d\u80fd\u8bbf\u95ee\u6b64\u9875\u9762\u3002\u5b83\u88ab\u79f0\u4e3a route constraints\uff0c\u4f60\u5728\u7b2c 4 \u7ae0\u4e2d\u4e86\u89e3\u4e86\u5b83\u3002\u76f8\u53cd\uff0c\u60a8\u53ef\u4ee5\u5c06 id \u8bbe\u4e3a\u6b64\u9875\u9762\u7684\u5fc5\u9700\u8def\u7531\u53c2\u6570\uff0c\u5e76\u5c06\u5176\u9650\u5236\u4e3a\u6570\u5b57\u7c7b\u578b\uff0c\u4ece\u800c\u4e0d\u9700\u8981\u7b2c\u4e00\u4e2a\u4ee3\u7801\u5757\uff0c\u56e0\u4e3a\u5982\u679c\u672a\u63d0\u4f9b\u6570\u5b57\uff0c\u6846\u67b6\u5c06\u8fd4\u56de 404\u3002<\/p>\n
      \u6b64\u4ee3\u7801\u5757\u5c06\u521b\u5efa\u4e00\u4e2a\u586b\u5145\u4e86 City \u6570\u636e\u7684 SelectList\u3002SelectList \u88ab\u5206\u914d\u7ed9 ViewData\uff0c\u6b63\u5982\u60a8\u53ef\u80fd\u8fd8\u8bb0\u5f97\u7b2c 3 \u7ae0\u4e2d\u7684\u90a3\u6837\uff0c\u5b83\u662f\u4e00\u4e2a\u5f31\u7c7b\u578b\u5b57\u5178\u3002\u4ece ViewData \u68c0\u7d22\u5230\u7684\u5bf9\u8c61\u9700\u8981\u5f3a\u5236\u8f6c\u6362\u4e3a\u5176\u6b63\u786e\u7684\u7c7b\u578b\uff0c\u4ee5\u4fbf\u5728\u4ee3\u7801\u4e2d\u518d\u6b21\u4f7f\u7528\u3002\u7406\u60f3\u60c5\u51b5\u4e0b\uff0cSelectList \u5e94\u8be5\u662f PageModel \u7684\u4e00\u4e2a\u5c5e\u6027\uff0c\u56e0\u6b64\u5728 Razor \u9875\u9762\u4e2d\u4f7f\u7528\u5bf9\u8c61\u65f6\uff0c\u65e0\u9700\u4f7f\u7528\u5f3a\u5236\u8f6c\u6362\u3002<\/p>\n
      \u83b7\u53d6 city \u6570\u636e\u7684\u4ee3\u7801\u4e0d\u662f\u5f02\u6b65\u7684\u3002\u4f5c\u4e3a\u6027\u80fd\u6700\u4f73\u5b9e\u8df5\uff0c\u60a8\u5e94\u8be5\u59cb\u7ec8\u81f4\u529b\u4e8e\u5728 ASP.NET Core Web \u5e94\u7528\u7a0b\u5e8f\u4e2d\u4f7f\u7528\u5f02\u6b65 API\uff08\u5982\u679c\u5b83\u4eec\u53ef\u7528 http:\/\/mng.bz\/epwV\uff09\u3002\u5927\u591a\u6570\u8fdb\u884c\u8fdb\u7a0b\u5916\u8c03\u7528<\/a> \uff08I\/O\uff09 \u7684\u5e93\uff08\u4f8b\u5982\uff0c\u652f\u6301\u4e0e\u6570\u636e\u5e93\u901a\u4fe1\u3001\u53d1\u9001\u7535\u5b50\u90ae\u4ef6\u3001\u6587\u4ef6\u5904\u7406\u7b49\u7684\u5e93\uff09\u90fd\u63d0\u4f9b\u5f02\u6b65 API\u3002<\/p>\n
      \u5f02\u6b65\u4ee3\u7801\u7684\u539f\u56e0<\/h2>\n
      \u60f3\u8c61\u4e00\u4e0b\uff0c\u60a8\u6b63\u5728\u5b89\u88c5\u4e00\u4e2a\u53a8\u623f\u3002\u60a8\u7528 DIY \u5957\u4ef6\u6784\u5efa\u6a71\u67dc\uff0c\u4f46\u60a8\u4f1a\u53d1\u73b0\u5176\u4e2d\u4e00\u6247\u95e8\u7f3a\u5c11\u94f0\u94fe\u3002\u4f60\u51b3\u5b9a\u5728\u5f97\u5230\u94f0\u94fe\u4e4b\u524d\u4e0d\u80fd\u524d\u8fdb\uff0c\u6240\u4ee5\u4f60\u5f00\u8f66\u53bb\u5546\u5e97\u62ff\u4e00\u4e2a\u3002\u60a8\u5f00\u8f66\u53bb\u5546\u5e97\u7684\u6240\u6709\u65f6\u95f4\u90fd\u88ab\u6d6a\u8d39\u4e86\uff0c\u5e76\u589e\u52a0\u4e86\u60a8\u7684\u4efb\u52a1\u5ef6\u8fdf\u3002\u60a8\u6b63\u5728\u540c\u6b65\u5de5\u4f5c\uff0c\u5728\u8fdb\u5165\u4e0b\u4e00\u4e2a\u4efb\u52a1\u4e4b\u524d\u5b8c\u6210\u4e00\u4e2a\u4efb\u52a1\u3002
      \n\u5bf9\u4e8e\u8fd9\u79cd\u60c5\u51b5\uff0c\u66f4\u6709\u6548\u7684\u65b9\u6cd5\u662f\u81f4\u7535 store \u5e76\u8ba9\u4ed6\u4eec\u63d0\u4f9b\u4e00\u4e2a hinge\u3002\u8fd9\u6837\uff0c\u60a8\u5c31\u53ef\u4ee5\u7ee7\u7eed\u6267\u884c\u5176\u4ed6\u4efb\u52a1\uff0c\u540c\u65f6\u7b49\u5f85\u60a8\u59d4\u6d3e\u7ed9\u5546\u5e97\u7684\u914d\u9001\u4efb\u52a1\u5df2\u5b8c\u6210\u7684\u901a\u77e5\uff08\u95e8\u94c3\u54cd\u8d77\uff09\u3002\u8fd9\u5c31\u662f\u5f02\u6b65\u7f16\u7a0b\u7684\u5de5\u4f5c\u539f\u7406\u3002
      \nWeb \u670d\u52a1\u5668\u7684\u53ef\u7528\u7ebf\u7a0b\u6570\u6709\u9650\uff0c\u5728\u9ad8\u8d1f\u8f7d\u60c5\u51b5\u4e0b\uff0c\u6240\u6709\u53ef\u7528\u7ebf\u7a0b\u90fd\u53ef\u80fd\u6b63\u5728\u4f7f\u7528\u4e2d\u3002\u53d1\u751f\u8fd9\u79cd\u60c5\u51b5\u65f6\uff0c\u670d\u52a1\u5668\u65e0\u6cd5\u5904\u7406\u65b0\u8bf7\u6c42\uff0c\u76f4\u5230\u7ebf\u7a0b\u88ab\u91ca\u653e\u3002\u4f7f\u7528\u540c\u6b65\u4ee3\u7801\u65f6\uff0c\u8bb8\u591a\u7ebf\u7a0b\u53ef\u80fd\u4f1a\u5728\u5b9e\u9645\u4e0a\u6ca1\u6709\u6267\u884c\u4efb\u4f55\u5de5\u4f5c\u65f6\u88ab\u5360\u7528\uff0c\u56e0\u4e3a\u5b83\u4eec\u6b63\u5728\u7b49\u5f85 I\/O\uff08\u5982\u6570\u636e\u5e93\u8c03\u7528\uff09\u5b8c\u6210\u3002\u4f7f\u7528\u5f02\u6b65\u4ee3\u7801\u65f6\uff0c\u5f53\u8fdb\u7a0b\u7b49\u5f85 I\/O \u5b8c\u6210\u65f6\uff0c\u5176\u7ebf\u7a0b\u5c06\u88ab\u91ca\u653e\u4f9b\u670d\u52a1\u5668\u7528\u4e8e\u5904\u7406\u5176\u4ed6\u8bf7\u6c42\u3002\u56e0\u6b64\uff0c\u5f02\u6b65\u4ee3\u7801\u4f7f\u670d\u52a1\u5668\u8d44\u6e90\u80fd\u591f\u66f4\u6709\u6548\u5730\u4f7f\u7528\uff0c\u5e76\u4e14\u670d\u52a1\u5668\u80fd\u591f\u65e0\u5ef6\u8fdf\u5730\u5904\u7406\u66f4\u591a\u6d41\u91cf\u3002<\/p>\n
      \u751f\u6210\u4ee3\u7801\u7684\u4e0b\u4e00\u4e2a\u4e3b\u8981\u95ee\u9898\u4e4d\u4e00\u770b\u53ef\u80fd\u5e76\u4e0d\u660e\u663e\uff0c\u4f46\u5f53\u60a8\u8fd0\u884c\u5e94\u7528\u7a0b\u5e8f\u5e76\u5bfc\u822a\u5230 \/property-manager\/ edit\uff1fid=1 \u65f6\uff0c\u5b83\u5f88\u5feb\u5c31\u4f1a\u53d8\u5f97\u6e05\u6670\uff0c\u5982\u56fe 8.12 \u6240\u793a\u3002\u57ce\u5e02\u9009\u62e9\u5217\u8868\u4e2d\u663e\u793a\u7684\u503c\u662f\u952e\u503c\uff0c\u800c\u4e0d\u662f\u57ce\u5e02\u540d\u79f0\u3002<\/p>\n
      <\/p>\n
      \u56fe 8.12 \u952e\u503c\u663e\u793a\u5728\u9009\u62e9\u5217\u8868\u4e2d\uff0c\u800c\u4e0d\u662f\u57ce\u5e02\u540d\u79f0\u4e2d\u3002<\/p>\n
      \u60a8\u7684\u8865\u6551\u8ba1\u5212\u5c06\u6267\u884c\u4ee5\u4e0b\u4f5c\uff1a<\/p>\n
        \n
      1. \u5c06\u6ce8\u5165\u7684\u4e0a\u4e0b\u6587\u4ea4\u6362\u4e3a\u670d\u52a1\uff0c\u4ece\u800c\u542f\u7528\u677e\u6563\u8026\u5408\u3002<\/li>\n
      2. \u7ed1\u5b9a\u5230\u5355\u4e2a\u5c5e\u6027\u4ee5\u964d\u4f4e\u5b89\u5168\u98ce\u9669\u3002<\/li>\n
      3. \u51cf\u5c11\u5bf9 ViewData \u7684\u4f9d\u8d56\u3002<\/li>\n
      4. \u5c3d\u53ef\u80fd\u4f7f\u7528\u5f02\u6b65\u4ee3\u7801\u3002<\/li>\n<\/ol>\n
        8.5 \u521b\u5efa\u3001\u4fee\u6539\u548c\u5220\u9664\u6570\u636e<\/h2>\n
        \u5728\u672c\u8282\u4e2d\uff0c\u60a8\u5c06\u521b\u5efa\u4e00\u4e2a PropertyService \u4ee5\u6ee1\u8db3\u57fa\u67b6\u9875\u9762\u5904\u7406\u7684\u65b9\u6848\u7684\u8981\u6c42\u3002\u60a8\u5c06\u6dfb\u52a0\u7528\u4e8e\u521b\u5efa\u548c\u7f16\u8f91 Property \u5b9e\u4f53\u7684\u65b9\u6cd5\uff0c\u5e76\u6839\u636e\u5176\u952e\u503c\u68c0\u7d22\u5355\u4e2a\u5b9e\u4f8b\u3002\u60a8\u6682\u65f6\u4e0d\u4f1a\u751f\u6210\u7528\u4e8e\u5220\u9664\u5b9e\u4f53\u7684\u65b9\u6cd5\u3002\u7a0d\u540e\uff0c\u60a8\u5c06\u5feb\u901f\u67e5\u770b\u4ece\u6570\u636e\u5e93\u4e2d\u5220\u9664\u9879\u76ee\u6240\u9700\u7684\u4ee3\u7801\uff0c\u4f46\u5bf9\u4e8e\u6b64\u5e94\u7528\u7a0b\u5e8f\uff0c\u60a8\u5c06\u4f7f\u7528\u8f6f\u5220\u9664\uff0c\u5c06\u9879\u76ee\u6807\u8bb0\u4e3a\u5df2\u5220\u9664\uff0c\u800c\u4e0d\u5b9e\u9645\u5220\u9664\u5b83\u3002<\/p>\n
        \u5728 EF Core \u4e2d\uff0c\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528 DbContext \u7684 Add\u3001Update \u548c Remove \u65b9\u6cd5\u5bf9 DbContext \u6267\u884c\u5bfc\u81f4\u6dfb\u52a0\u3001\u66f4\u65b0\u6216\u5220\u9664\u6570\u636e\u7684\u4f5c\u3002\u8fd9\u4e9b\u65b9\u6cd5\u4e2d\u7684\u6bcf\u4e00\u79cd\u90fd\u5c06\u8981\u4f5c\u7684\u5b9e\u4f53\u4f5c\u4e3a\u53c2\u6570\uff0c\u5e76\u5c06\u5176\u72b6\u6001\u8bbe\u7f6e\u4e3a Added\u3001Modified \u6216 Deleted \u4e4b\u4e00\u3002\u60a8\u5c06\u8c03\u7528 DbContext \u7684\u5f02\u6b65 SaveChangesAsync \u65b9\u6cd5\uff0c\u4ee5\u5c06\u66f4\u6539\u63d0\u4ea4\u5230\u6570\u636e\u5e93\u3002\u4e0a\u4e0b\u6587\u5c06\u6839\u636e\u5b9e\u4f53\u7684\u72b6\u6001\u751f\u6210\u76f8\u5e94\u7684 SQL\u3002\u6b64\u5de5\u4f5c\u6d41\u5982\u56fe 8.13 \u6240\u793a\u3002<\/p>\n
        <\/p>\n
        \u56fe 8.13 Add \u65b9\u6cd5\u5c06\u5b9e\u4f53\u7684\u72b6\u6001\u8bbe\u7f6e\u4e3a Added\u3002\u8c03\u7528 SaveChangesAsync \u65f6\uff0cEF Core \u4f1a\u751f\u6210\u4e00\u4e2a SQL INSERT \u8bed\u53e5\uff0c\u5e76\u9488\u5bf9\u6570\u636e\u5e93\u6267\u884c\u8be5\u8bed\u53e5\u3002<\/p>\n
        \u56e0\u6b64\uff0c\u8ba9\u6211\u4eec\u9996\u5148\u4e3a\u5c01\u88c5\u8fd9\u4e9b\u4f5c\u7684 Property \u5b9e\u4f53\u521b\u5efa\u670d\u52a1\u7c7b\u3002\u7b2c\u4e00\u6b65\u662f\u5c06\u540d\u4e3a IPropertyService \u7684\u65b0\u63a5\u53e3\u6dfb\u52a0\u5230\u201c\u670d\u52a1\u201d\u6587\u4ef6\u5939\u4e2d\uff0c\u5176\u4e2d\u5305\u542b\u4ee5\u4e0b\u4ee3\u7801\u3002<\/p>\n
        \u6e05\u5355 8.24 \u5e26\u6709 CRUD \u65b9\u6cd5\u7684 IPropertyService \u63a5\u53e3<\/p>\n
        using CityBreaks.Models;\n\nnamespace CityBreaks.Services\n{\n    public interface IPropertyService\n    {\n        Task<Property> CreateAsync(Property property);\n        Task<List<Property>> GetAllAsync();\n        Task<Property> FindAsync(int id);\n        Task<Property> UpdateAsync(Property property);\n        Task DeleteAsync(int id);\n    }\n}<\/code><\/pre>\n
        \u73b0\u5728\uff0c\u5c06\u4e00\u4e2a\u540d\u4e3a PropertyService \u7684\u65b0\u7c7b\u6dfb\u52a0\u5230\u5b9e\u73b0\u8be5\u63a5\u53e3\u7684 Services \u6587\u4ef6\u5939\u4e2d\u3002<\/p>\n
        \u6e05\u5355 8.25 \u5728 PropertyService \u4e2d\u5b9e\u73b0 CRUD \u65b9\u6cd5<\/p>\n
        using CityBreaks.Data;\nusing CityBreaks.Models;\nusing Microsoft.EntityFrameworkCore;\n\nnamespace CityBreaks.Services;\npublic class PropertyService : IPropertyService\n{\n    private readonly CityBreaksContext _context;\n\n    public PropertyService(CityBreaksContext context) =>\n        _context = context;\n\n    public async Task<Property> FindAsync(int id) =>\n        await _context.Properties\n        .FindAsync(id);\n\n    public async Task<List<Property>> GetAllAsync() =>\n        await _context.Properties\n        .Include(x => x.City)\n        .ToListAsync();\n\n    public async Task<Property> CreateAsync(Property property)\n    {\n        _context.Add(property);\n        await _context.SaveChangesAsync();\n        return property;\n    }\n\n    public async Task<Property> UpdateAsync(Property property)\n    {\n        _context.Update(property);\n        await _context.SaveChangesAsync();\n        return property;\n    }\n}<\/code><\/pre>\n
        \u7b2c\u4e00\u79cd\u65b9\u6cd5\u4f7f\u7528 FindAsync \u65b9\u6cd5\u68c0\u7d22\u5355\u4e2a\u5b9e\u4f53\u3002\u6b64\u65b9\u6cd5\u4e0e\u60a8\u76ee\u524d\u770b\u5230\u7684\u4ee5 First \u548c Single \u5f00\u5934\u7684\u65b9\u6cd5\u4e0d\u540c\u3002\u5b83\u9700\u8981\u4e00\u4e2a\u503c\uff0c\u8be5\u503c\u8868\u793a\u8981\u68c0\u7d22\u7684\u5b9e\u4f53\u7684\u952e\uff0c\u4f46\u4e0d\u80fd\u5c06\u5176\u4e0e Include \u65b9\u6cd5\u4e00\u8d77\u4f7f\u7528\u3002\u7f16\u8f91\u9879\u76ee\u65f6\uff0c\u60a8\u4e0d\u4e00\u5b9a\u9700\u8981\u5176\u5173\u8054\u6570\u636e;\u60a8\u53ea\u9700\u8981 Foreign key \u503c\u3002FindAsync \u65b9\u6cd5\u975e\u5e38\u9002\u5408\u6b64\u76ee\u7684\u3002<\/p>\n
        CreateAsync \u65b9\u6cd5\u4f7f\u7528 DbContext.Add \u65b9\u6cd5\u83b7\u53d6\u4e0a\u4e0b\u6587\u4ee5\u5f00\u59cb\u8ddf\u8e2a\u5c5e\u6027\u5b9e\u4f53\u3002EntityState \u5e94\u7528\u4e8e\u4e0a\u4e0b\u6587\u8ddf\u8e2a\u7684\u6240\u6709\u5b9e\u4f53\uff0c\u8fd9\u662f\u4e00\u4e2a\u6307\u5b9a\u5b9e\u4f53\u5f53\u524d\u72b6\u6001\u7684\u679a\u4e3e\u3002\u4f7f\u7528 Add \u65b9\u6cd5\u65f6\uff0c\u5c06\u5206\u914d EntityState.Added \u503c\u3002\u8fd9\u544a\u8bc9\u4e0a\u4e0b\u6587\u5e94\u8be5\u5c06\u5b9e\u4f53\u6dfb\u52a0\u4e3a\u65b0\u8bb0\u5f55\uff0c\u5e76\u4e14\u751f\u6210\u7684 SQL \u662f INSERT \u8bed\u53e5\u3002<\/p>\n
        DbContext.Add \u65b9\u6cd5\u662f\u5728 EF Core \u4e2d\u5f15\u5165\u7684\u3002\u5728\u65e9\u671f\u7248\u672c\u7684 EF \u4e2d\uff0c\u5bf9\u76f8\u5173\u7684 DbSet \u6267\u884c\u6570\u636e\u4f5c\uff0c\u7b49\u6548\u7684<\/p>\n
        _context.Properties.Add(property)<\/code><\/pre>\n
        UpdateAsync \u65b9\u6cd5\u4f7f\u7528 DbContext.Update \u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u6307\u793a\u4e0a\u4e0b\u6587\u5f00\u59cb\u8ddf\u8e2a\u5904\u4e8e EntityState.Modified \u72b6\u6001\u7684\u5b9e\u4f53\u3002DbContext .Update \u65b9\u6cd5\u4e5f\u662f EF Core \u4e2d\u7684\u65b0\u589e\u529f\u80fd\u3002\u5728\u65e9\u671f\u7248\u672c\u7684 EF \u4e2d\uff0c\u60a8\u5fc5\u987b\u5c06\u4fee\u6539\u540e\u7684\u5b9e\u4f53\u9644\u52a0\u5230\u4e0a\u4e0b\u6587\uff0c\u5e76\u5c06\u5176\u72b6\u6001\u663e\u5f0f\u8bbe\u7f6e\u4e3a EntityState.Modified\uff0c\u8fd9\u7c7b\u4f3c\u4e8e\u5df2\u5e94\u7528\u4e8e\u57fa\u67b6\u4ee3\u7801\u4e2d\u73b0\u6709 OnPostAsync \u5904\u7406\u7a0b\u5e8f\u7684\u6a21\u5f0f\uff1a<\/p>\n
        _context.Attach(Property).State = EntityState.Modified;
        \n\u5f53\u5b9e\u4f53\u5904\u4e8e Modified \u72b6\u6001\u65f6\uff0cEF Core \u4f1a\u751f\u6210\u4e00\u4e2a SQL UPDATE \u8bed\u53e5\uff0c\u8be5\u8bed\u53e5\u4f1a\u5bfc\u81f4\u4fee\u6539\u5b9e\u4f53\u7684\u6240\u6709\u975e\u952e\u503c\u3002\u6211\u4eec\u5c06\u4e86\u89e3\u5982\u4f55\u63a7\u5236 SQL\uff0c\u4ee5\u4fbf\u5b83\u4ec5\u5728\u60a8\u7a0d\u540e\u5b9e\u65bd\u8f6f\u5220\u9664\u65f6\u66f4\u65b0\u5355\u4e2a\u5c5e\u6027\u503c\u3002<\/p>\n
        CreateAsync \u548c UpdateAsync \u65b9\u6cd5\u90fd\u5305\u542b\u540c\u4e00\u884c\uff1a<\/p>\n
        await _context.SaveChangesAsync();<\/code><\/pre>\n
        SaveChangesAsync \u65b9\u6cd5\u4f1a\u5bfc\u81f4\u5bf9\u6570\u636e\u7684\u6240\u6709\u6302\u8d77\u66f4\u6539\u5199\u5165\u6570\u636e\u5e93\u3002\u5b83\u8fd4\u56de\u4e00\u4e2a int\uff0c\u8868\u793a\u53d7\u4f5c\u5f71\u54cd\u7684\u884c\u6570\u3002\u5f53\u60a8\u4f7f\u7528 Add \u65b9\u6cd5\u521b\u5efa\u65b0\u8bb0\u5f55\u65f6\uff0c\u751f\u6210\u7684 SQL \u4f1a\u68c0\u7d22\u65b0\u521b\u5efa\u8bb0\u5f55\u7684\u4e3b\u952e\u503c\uff0cEF Core \u4f1a\u5c06\u5176\u5206\u914d\u7ed9\u8ddf\u8e2a\u7684\u5b9e\u4f53\u3002\u60a8\u7684\u6570\u636e\u5e93\u4f5c\u975e\u5e38\u7b80\u5355\uff0c\u53ea\u6d89\u53ca\u4e00\u4e2a\u547d\u4ee4\u3002\u53ef\u4ee5\u8bbe\u7f6e\u591a\u4e2a\u4f5c\uff0c\u5e76\u901a\u8fc7\u5bf9 SaveChangesAsync \u7684\u4e00\u6b21\u8c03\u7528\u540c\u65f6\u63d0\u4ea4\u6240\u6709\u4f5c\u3002\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0cEF Core \u4f7f\u7528\u4e8b\u52a1\u6765\u6267\u884c\u8fd9\u4e9b\u4f5c\uff0c\u56e0\u6b64\uff0c\u5982\u679c\u5176\u4e2d\u4efb\u4f55\u4e00\u4e2a\u4f5c\u5931\u8d25\uff0c\u6240\u6709\u5176\u4ed6\u4f5c\u90fd\u5c06\u56de\u6eda\uff0c\u4ece\u800c\u4fdd\u6301\u6570\u636e\u5e93\u4e0d\u53d8\u3002<\/p>\n
        \u8be5\u670d\u52a1\u51e0\u4e4e\u5df2\u51c6\u5907\u597d\u66ff\u6362 PageModel \u4e2d\u7684 DbContext\u4f5c\u3002\u5728\u4ee3\u7801\u4e2d\u4f7f\u7528\u8be5\u670d\u52a1\u4e4b\u524d\uff0c\u5fc5\u987b\u5148\u5c06\u5176\u6ce8\u518c\u5230\u670d\u52a1\u5bb9\u5668\u3002\u8f6c\u5230 Program.cs\uff0c\u5e76\u6dfb\u52a0\u4ee5\u4e0b\u6ce8\u518c\uff1a<\/p>\n
        builder.Services.AddScoped<IPropertyService, PropertyService>();<\/code><\/pre>\n
        8.5.1 \u4fee\u6539\u6570\u636e<\/h3>\n
        \u8f6c\u5230\u57fa\u67b6 EditModel \u7c7b\uff0c\u60a8\u5c06\u8fdb\u884c\u4ee5\u4e0b\u66f4\u6539\uff0c\u4ee5\u5c06\u73b0\u6709\u7684\u79c1\u6709\u5b57\u6bb5\u66ff\u6362\u4e3a IPropertyService \u548c ICityService \u7684\u65b0\u79c1\u6709\u5b57\u6bb5\u3002\u6ce8\u5165\u7684\u4e0a\u4e0b\u6587\u5c06\u66ff\u6362\u4e3a\u670d\u52a1\u3002\u60a8\u8fd8\u9700\u8981\u6dfb\u52a0\u4e00\u4e2a using \u6307\u4ee4\u6765\u5f15\u7528 CityBreaks.Services\u3002<\/p>\n
        \u793a\u4f8b 8.26 \u6ce8\u5165 IPropertyService \u4ee3\u66ff DbContext<\/p>\n
        private readonly IPropertyService _propertyService;\nprivate readonly ICityService _cityService;\n\npublic EditModel(IPropertyService propertyService, ICityService cityService)\n{\n    _propertyService = propertyService;\n    _cityService = cityService; \n}<\/code><\/pre>\n
        \u5728\u6e05\u5355 8.27 \u6240\u793a\u7684\u6b65\u9aa4\u4e2d\uff0c\u60a8\u5c06 Property \u7ed1\u5b9a\u76ee\u6807\u66ff\u6362\u4e3a\u8868\u793a\u8981\u5411\u7528\u6237\u516c\u5f00\u7684\u503c\u7684\u5355\u4e2a\u7ed1\u5b9a\u76ee\u6807\u3002\u60a8\u8fd8\u53ef\u4ee5\u6dfb\u52a0\u4e00\u4e2a\u516c\u5171 SelectList \u5c5e\u6027\uff0c\u4ee5\u66ff\u6362\u5f53\u524d\u5bf9 city \u4e0b\u62c9\u5217\u8868\u91c7\u7528\u7684 ViewData \u65b9\u6cd5\u3002\u6700\u540e\uff0c\u5c06 OnGet \u5904\u7406\u7a0b\u5e8f\u53c2\u6570 \uff08id\uff09 \u66ff\u6362\u4e3a\u4e00\u4e2a\u516c\u5171\u5c5e\u6027\uff0c\u8be5\u5c5e\u6027\u4f7f\u60a8\u80fd\u591f\u5728\u4e24\u4e2a\u5904\u7406\u7a0b\u5e8f\u65b9\u6cd5\u4e2d\u4f7f\u7528\u8be5\u503c\uff0c\u5e76\u4e14\u60a8\u5c06\u786e\u4fdd\u5728\u8bf7\u6c42\u4f7f\u7528 GET \u65b9\u6cd5\u65f6\u53ef\u4ee5\u5c06\u5176\u7ed1\u5b9a\u5230\u8be5\u503c\u3002<\/p>\n
        \u6e05\u5355 8.27 \u5c06\u7ed1\u5b9a\u5230\u5b9e\u4f53\u66ff\u6362\u4e3a\u7ed1\u5b9a\u5230\u5c5e\u6027<\/p>\n
        public SelectList Cities { get; set; }\n[BindProperty(SupportsGet = true)]\npublic int Id { get; set; }\n[BindProperty, Display(Name = "City")]\npublic int CityId { get; set; }\n[BindProperty, Required]\npublic string Name { get; set; }\n[BindProperty, Required]\npublic string Address { get; set; }\n[BindProperty, Display(Name = "Maximum Number Of Guests")]\npublic int MaxNumberOfGuests { get; set; }\n[BindProperty, Display(Name = "Daily Rate")]\npublic decimal DayRate { get; set; }\n[BindProperty, Display(Name = "Smoking?")]\npublic bool SmokingPermitted { get; set; }\n[BindProperty, Display(Name = "Available From")]\npublic DateTime AvailableFrom { get; set; }<\/code><\/pre>\n
        \u60a8\u9700\u8981\u5728 OnGetAsync \u5904\u7406\u7a0b\u5e8f\u4e2d\u586b\u5145 Cities SelectList \u5c5e\u6027\uff0c\u5982\u679c\u5b58\u5728 ModelState \u9519\u8bef\uff0c\u5219\u9700\u8981\u5728 OnPostAsync \u5904\u7406\u7a0b\u5e8f\u4e2d\u518d\u6b21\u586b\u5145\u3002\u60a8\u5df2\u7ecf\u4e3a\u6b64\u5efa\u7acb\u4e86\u4e00\u4e2a\u51cf\u5c11\u91cd\u590d\u7684\u6a21\u5f0f\u3002\u5728\u5217\u8868 8.28 \u4e2d\uff0c\u4f60\u6dfb\u52a0\u4e86\u4e00\u4e2a\u79c1\u6709\u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2a SelectList\uff0c\u8be5\u65b9\u6cd5\u4f7f\u7528\u5f02\u6b65\u4ee3\u7801\u5230 PageModel \u7c7b\u7684\u672b\u5c3e\u3002<\/p>\n
        \u6e05\u5355 8.28 \u7528\u4e8e\u586b\u5145 SelectList \u5bf9\u8c61\u7684\u53ef\u91cd\u7528\u79c1\u6709\u65b9\u6cd5<\/p>\n
        private async Task<SelectList> GetCityOptions()\n{\n    var cities = await _cityService.GetAllAsync();\n    return new SelectList(cities, nameof(City.Id), nameof(City.Name));\n}<\/code><\/pre>\n
        \u73b0\u5728\uff0c\u4f60\u5c06\u770b\u5230\u8bb8\u591a\u7ea2\u8272\u6ce2\u6d6a\u7ebf\uff0c\u6307\u793a\u7f16\u8bd1\u5668\u9519\u8bef\u3002\u9996\u5148\u5728 OnGetAsync \u65b9\u6cd5\u4e2d\u5904\u7406\u8fd9\u4e9b\u95ee\u9898\uff0c\u65b9\u6cd5\u662f\u5c06\u6574\u4e2a\u65b9\u6cd5\u5757\u66ff\u6362\u4e3a\u4ee5\u4e0b\u4ee3\u7801\uff0c\u8be5\u4ee3\u7801\u4f7f\u7528\u8be5\u670d\u52a1\u83b7\u53d6\u8981\u7f16\u8f91\u7684 Property \u5b9e\u4f8b\uff0c\u5e76\u5c06\u5176\u503c\u5206\u914d\u7ed9\u516c\u5171 PageModel \u5c5e\u6027\u3002<\/p>\n
        \u6e05\u5355 8.29 \u4fee\u6539\u540e\u7684 OnGetAsync \u65b9\u6cd5<\/p>\n
        public async Task<IActionResult> OnGetAsync()\n{\n    var property = await _propertyService.FindAsync(Id);\n\n    if (property == null)\n    {\n        return NotFound();\n    }\n    Address = property.Address;\n    AvailableFrom = property.AvailableFrom;\n    CityId = property.CityId;\n    DayRate = property.DayRate;\n    MaxNumberOfGuests = property.MaxNumberOfGuests;\n    Name = property.Name;\n    SmokingPermitted = property.SmokingPermitted;\n\n    Cities = await GetCityOptions();\n    return Page();\n}<\/code><\/pre>\n
        \u5bf9\u4e8e\u76f8\u5bf9\u7b80\u5355\u7684\u5b9e\u4f53\uff0c\u5c06\u503c\u4ece\u6570\u636e\u5e93\u4e2d\u68c0\u7d22\u5230\u7684\u5b9e\u4f53\u6620\u5c04\u5230 PageModel \u5c5e\u6027\u7684\u4ee3\u7801\u662f\u53ef\u7ba1\u7406\u7684\u3002\u60a8\u53ef\u4ee5\u60f3\u8c61\uff0c\u5bf9\u4e8e\u5177\u6709\u66f4\u591a\u5c5e\u6027\u7684\u5b9e\u4f53\uff0c\u7f16\u5199\u548c\u7ef4\u62a4\u8fd9\u79cd\u7c7b\u578b\u7684\u4ee3\u7801\u5c06\u975e\u5e38\u8d39\u529b\u3002\u53ef\u4ee5\u4f7f\u7528\u4e00\u4e9b\u5de5\u5177\u6765\u5e2e\u52a9\u663e\u8457\u51cf\u5c11\u6b64\u4ee3\u7801\uff08\u5728\u8bb8\u591a\u60c5\u51b5\u4e0b\uff0c\u51cf\u5c11\u5230\u4e00\u884c\u4ee3\u7801\uff09\uff0c\u4f8b\u5982\u6d41\u884c\u7684 AutoMapper \uff08https:\/\/automapper.org\/\uff09\uff0c\u8fd9\u662f\u6211\u7684\u9996\u9009\u9009\u9879\u3002\u5728\u672c\u4e66\u4e2d\uff0c\u60a8\u4e0d\u4f1a\u4f7f\u7528\u8fd9\u6837\u7684\u5de5\u5177\uff0c\u4f46\u6211\u5efa\u8bae\u60a8\u4e3a\u81ea\u5df1\u7684\u5e94\u7528\u7a0b\u5e8f\u63a2\u7d22\u8fd9\u79cd\u8282\u7701\u5927\u91cf\u65f6\u95f4\u7684\u5de5\u5177<\/a>\u3002<\/p>\n
        \u8fd9\u6837\uff0c\u5728\u79fb\u52a8\u9875\u9762\u7684 Razor \u90e8\u5206\u4e4b\u524d\uff0c\u53ea\u9700\u6574\u7406 OnPostAsync \u65b9\u6cd5\u5373\u53ef\u3002\u57fa\u67b6\u4ee3\u7801\u5c06\u6355\u83b7 DbUpdateConcurrencyException\uff08\u5982\u679c\u5f15\u53d1\uff09\uff0c\u8fd9\u8868\u793a\u60a8\u6b63\u5728\u7f16\u8f91\u7684\u9879\u4e0d\u518d\u5b58\u5728;\u5728\u60a8\u4ece\u6570\u636e\u5e93\u4e2d\u68c0\u7d22\u5b83\u5e76\u63d0\u4ea4\u60a8\u7684\u4fee\u6539\u4e4b\u95f4\uff0c\u5176\u4ed6\u4eba\u5df2\u7ecf\u5220\u9664\u4e86\u5b83\u3002\u8fd9\u4e0d\u662f\u60a8\u9700\u8981\u62c5\u5fc3\u7684\u60c5\u51b5\uff0c\u56e0\u4e3a\u60a8\u4e0d\u4f1a\u4ece\u6570\u636e\u5e93\u4e2d\u5220\u9664\u6761\u76ee\u3002\u6240\u4ee5\u4f60\u7684\u4efb\u52a1\u5f88\u7b80\u5355\u3002\u68c0\u67e5 ModelState\uff0c\u5982\u679c\u6709\u6548\uff0c\u5219\u5c06\u53d1\u5e03\u7684\u503c\u4f5c\u4e3a Property \u5b9e\u4f8b\u4f20\u9012\u7ed9\u670d\u52a1\u7684 UpdateAsync \u65b9\u6cd5\u3002<\/p>\n
        \u793a\u4f8b 8.30 \u66f4\u65b0\u7684 OnPostAsync \u65b9\u6cd5<\/p>\n
        public async Task<IActionResult> OnPostAsync()\n{\n    if (!ModelState.IsValid)\n    {\n        Cities = await GetCityOptions();\n        return Page();\n    }\n\n    var property = new Property\n    {\n        Address = Address,\n        AvailableFrom = AvailableFrom,\n        CityId = CityId,\n        DayRate = DayRate,Id = Id,\n        MaxNumberOfGuests = MaxNumberOfGuests,\n        Name = Name,\n        SmokingPermitted = SmokingPermitted\n    };\n    await _propertyService.UpdateAsync(property);\n\n    return RedirectToPage(".\/Index");\n}<\/code><\/pre>\n
        \u60a8\u5df2\u5230\u8fbe\u8f6c\u6362\u7684\u6700\u540e\u4e00\u90e8\u5206\uff1aRazor \u9875\u9762\u672c\u8eab\u3002\u8fd9\u91cc\u4e0d\u9700\u8981\u592a\u591a\u66f4\u6539\u3002\u60a8\u9700\u8981\u505a\u7684\u5c31\u662f<\/p>\n
        \u2022  \u6dfb\u52a0\u8def\u7531\u6a21\u677f\u3002
        \n\u2022  \u4ece\u6807\u8bb0\u5e2e\u52a9\u7a0b\u5e8f\u6a21\u578b\u8868\u8fbe\u5f0f\u4e2d\u5220\u9664 Property \u524d\u7f00\u3002
        \n\u2022  \u66f4\u65b0 cities select \u5217\u8868\u4e2d\u7684 city \u6570\u636e\u6e90\u3002<\/p>\n
        \u9664\u975e\u5728 URL \u4e2d\u4f20\u9012\u6570\u5b57\uff0c\u5426\u5219\u60a8\u4e0d\u5e0c\u671b\u8bbf\u95ee\u6b64\u9875\u9762\uff0c\u56e0\u6b64\u8def\u7531\u6a21\u677f\u5fc5\u987b\u5305\u542b\u7ea6\u675f\u3002\u56e0\u6b64\uff0c\u60a8\u5c06\u4ee5\u4e0b\u6a21\u677f\u6dfb\u52a0\u5230 @page \u6307\u4ee4\u4e2d\uff1a<\/p>\n
        @page "{id:int}"<\/code><\/pre>\n
        \u60a8\u5728 URL \u4e2d\u6709 id\uff0c\u5e76\u4e14\u60a8\u5df2\u5728 PageModel \u4e2d\u542f\u7528\u4e86\u4e0e route \u53c2\u6570\u7684\u7ed1\u5b9a\uff0c\u56e0\u6b64\u60a8\u4e0d\u518d\u9700\u8981\u8868\u5355\u4e2d\u7684 hidden \u5b57\u6bb5\uff1a<\/p>\n
        <input type="hidden" asp-for="Property.Id" \/><\/code><\/pre>\n
        \u60a8\u53ef\u4ee5\u5c06\u5176\u6ce8\u91ca\u6389\u6216\u5b8c\u5168\u5220\u9664\u3002\u63a5\u4e0b\u6765\uff0c\u627e\u5230 cities select list \u7684 HTML \u90e8\u5206\uff0c\u5982\u4e0b\u9762\u7684\u6e05\u5355\u6240\u793a\u3002<\/p>\n
        Listing 8.31 \u811a\u624b\u67b6\u9009\u62e9\u5217\u8868 HTML<\/p>\n
        <div class="form-group">\n    <label asp-for="Property.CityId" class="control-label"><\/label>\n    <select asp-for="Property.CityId" class="form-control" \n     \u27a5 asp-items="ViewBag.CityId"><\/select>\n    <span asp-validation-for="Property.CityId" class="text-danger"><\/span>\n<\/div><\/code><\/pre>\n
        \u6240\u6709\u5bf9 Property \u7684\u5f15\u7528\u90fd\u5e94\u5177\u6709\u7ea2\u8272\u6ce2\u6d6a\u7ebf\uff0c\u8868\u793a\u7f16\u8bd1\u5668\u9519\u8bef\u3002\u60a8\u9700\u8981\u5220\u9664\u5b83\u4eec\uff0c\u4ee5\u53ca\u9875\u9762\u4e2d\u5176\u4ed6\u6807\u7b7e\u5e2e\u52a9\u7a0b\u5e8f\u4e2d\u7684\u90a3\u4e9b\u3002\u60a8\u8fd8\u9700\u8981\u66f4\u65b0 asp-items \u5c5e\u6027\u4ee5\u5f15\u7528 Model.Cities \u800c\u4e0d\u662f ViewBag.CityId\u3002\u4fee\u6539\u540e\u7684\u7248\u672c\u5982\u4e0b\u9762\u7684\u6e05\u5355\u6240\u793a\u3002<\/p>\n
        \u5217\u8868 8.32 \u4fee\u6539\u540e\u7684\u9009\u62e9\u5217\u8868<\/p>\n
        <div class="form-group">\n    <label asp-for="CityId" class="control-label"><\/label>\n    <select asp-for="CityId" class="form-control" \n     \u27a5 asp-items="Model.Cities"><\/select>\n    <span asp-validation-for="CityId" class="text-danger"><\/span>\n<\/div><\/code><\/pre>\n
        \u73b0\u5728\uff0c\u60a8\u53ef\u4ee5\u6d4b\u8bd5\u4fee\u8ba2\u7248\u4e86\u3002\u8fd0\u884c\u5e94\u7528\u7a0b\u5e8f\uff0c\u7136\u540e\u5bfc\u822a\u5230 \/property-manager\u3002\u60a8\u5c06\u88ab\u5e26\u5230\u811a\u624b\u67b6\u7d22\u5f15\u9875\u9762\uff0c\u5176\u4e2d\u5217\u51fa\u4e86\u6240\u6709\u5c5e\u6027\uff08\u56fe 8.14\uff09\u3002<\/p>\n
        <\/p>\n
        \u56fe 8.14 \u539f\u59cb\u57fa\u67b6\u7d22\u5f15\u9875<\/p>\n
        \u8bf7\u8bb0\u4f4f\uff0c\u8fd9\u662f\u672a\u4fee\u6539\u7684\u57fa\u67b6\u7248\u672c\uff0c\u56e0\u6b64\u5b83\u5728 City \u5217\u4e2d\u663e\u793a\u952e\u503c\uff0c\u800c\u4e0d\u662f Name \u5217\u3002\u952e\u503c\u4e5f\u663e\u793a\u5728 Create \u9875\u9762\u7684\u9009\u62e9\u5217\u8868\u4e2d\uff0c\u60a8\u53ef\u4ee5\u901a\u8fc7\u5355\u51fb\u9875\u9762\u6807\u9898\u4e0b\u65b9\u7684 Create New \u94fe\u63a5\u6765\u8bbf\u95ee\u8be5\u5217\u8868\u3002\u5b83\u4eec\u4e5f\u4f1a\u663e\u793a\u5728\u6bcf\u4e2a\u5c5e\u6027\u7684 Details \uff08\u8be6\u7ec6\u4fe1\u606f\uff09 \u9875\u9762\u4e0a\u3002\u5355\u51fb\u5176\u4e2d\u4e00\u4e2a\u5c5e\u6027\u7684 Edit \u94fe\u63a5\uff0c\u67e5\u770b\u5b83\u4e0e\u57fa\u67b6\u7684 Create \u9875\u9762\u6709\u4f55\u4e0d\u540c\u3002\u57ce\u5e02\u7684\u540d\u79f0\u51fa\u73b0\u5728\u9009\u62e9\u5217\u8868\u4e2d\uff0c\u8868\u5355\u6807\u7b7e\u662f\u7528\u6237\u53cb\u597d\u7684\uff08\u56fe 8.15\uff09\u3002<\/p>\n
        <\/p>\n
        \u56fe 8.15 \u4fee\u6539\u540e\u7684 Edit \u9875\u9762<\/p>\n
        \u901a\u8fc7\u5c06 Available From date \u8bbe\u7f6e\u4e3a\u5c06\u6765\u7684\u65e5\u671f\u6765\u66f4\u6539\u8be5\u5c5e\u6027\u3002\u63d0\u4ea4\u8fd9\u4e9b\u66f4\u6539\uff0c\u5e76\u5728\u60a8\u5c06\u91cd\u5b9a\u5411\u5230 Index \u9875\u9762\u65f6\u786e\u8ba4\u60a8\u7684\u4fee\u8ba2\u6709\u6548\uff0c\u8be5\u9875\u9762\u5e94\u663e\u793a\u4fee\u8ba2\u65e5\u671f\u3002\u7136\u540e\u5bfc\u822a\u5230\u4e3b\u9875\uff0c\u5e76\u786e\u8ba4\u6307\u5b9a\u57ce\u5e02\u7684\u623f\u4ea7\u6570\u91cf\u5df2\u51cf\u5c11 1\u3002<\/p>\n
        8.5.2 \u5220\u9664\u6570\u636e<\/h3>\n
        \u57fa\u67b6\u9875\u9762\u5305\u62ec\u4e00\u4e2a\u7528\u4e8e\u5220\u9664\u5b9e\u4f53\u7684\u9875\u9762\u3002DeleteModel \u7c7b\u4e2d\u7684 OnPostAysnc \u65b9\u6cd5\u5305\u542b\u5b9e\u9645\u4ece\u6570\u636e\u5e93\u4e2d\u5220\u9664\u8be5\u6761\u76ee\u7684\u4ee3\u7801\u3002\u4e86\u89e3\u5b83\u7684\u5de5\u4f5c\u539f\u7406\u5f88\u91cd\u8981\uff0c\u56e0\u4e3a\u5b83\u4e0d\u662f\u6700\u4f18\u7684\u3002<\/p>\n
        \u6e05\u5355 8.33 DeleteModel \u4e2d\u7684\u57fa\u67b6 OnPostAsync \u65b9\u6cd5<\/p>\n
        public async Task<IActionResult> OnPostAsync(int? id)\n{\n    if (id == null)                                         \u2776\n    {                                                       \u2776\n        return NotFound();                                  \u2776\n    }                                                       \u2776\n\n    Property = await _context.Properties.FindAsync(id);     \u2777\n\n    if (Property != null)\n    {\n        _context.Properties.Remove(Property);               \u2778\n        await _context.SaveChangesAsync();                  \u2779\n    }\n\n    return RedirectToPage(".\/Index");\n}<\/code><\/pre>\n
        \u2776 \u68c0\u67e5\u662f\u5426\u5df2\u5c06\u952e\u503c\u4f20\u9012\u7ed9\u65b9\u6cd5
        \n\u2777 \u8fd9\u5c06\u4ece\u6570\u636e\u5e93\u4e2d\u68c0\u7d22\u5339\u914d\u7684\u6761\u76ee\u3002\u4e0a\u4e0b\u6587\u5f00\u59cb\u8ddf\u8e2a\u5b83\u3002
        \n\u2778 DbSet.Remove \u65b9\u6cd5\u5c06\u5b9e\u4f53\u7684\u72b6\u6001\u8bbe\u7f6e\u4e3a Deleted\u3002
        \n\u2779 SaveChangesAsync \u5c06\u66f4\u6539\u63d0\u4ea4\u5230\u6570\u636e\u5e93\u3002<\/p>\n
        \u6211\u4eec\u5df2\u7ecf\u8ba8\u8bba\u4e86\u5982\u4f55\u4f7f\u7528\u8def\u7531\u7ea6\u675f\u6765\u66ff\u6362\u6b64\u65b9\u6cd5\u5f00\u59cb\u65f6\u7684 null \u68c0\u67e5\u3002\u57fa\u67b6\u4ee3\u7801\u7684\u53e6\u4e00\u4e2a\u6b21\u4f18\u529f\u80fd\u662f\uff0c\u5b83\u4f1a\u5bfc\u81f4\u5bf9\u6570\u636e\u5e93\u6267\u884c\u4e24\u4e2a\u547d\u4ee4\u3002\u7b2c\u4e00\u4e2a\u547d\u4ee4\u4ece\u6570\u636e\u5e93\u4e2d\u68c0\u7d22\u9879\u76ee\uff0c\u4ee5\u4fbf\u4e0a\u4e0b\u6587\u53ef\u4ee5\u5f00\u59cb\u8ddf\u8e2a\u5b83\u3002\u8be5\u4ee3\u7801\u4f7f\u7528 DbSet.Remove \u65b9\u6cd5\u5c06\u5b9e\u4f53\u7684\u72b6\u6001\u8bbe\u7f6e\u4e3a Deleted\u3002\u7b2c\u4e8c\u4e2a\u547d\u4ee4\u5728\u8c03\u7528 SaveChangesAsync \u65f6\u6267\u884c\uff0c\u7531\u4e00\u4e2a SQL DELETE \u8bed\u53e5\u7ec4\u6210\uff0c\u8be5\u8bed\u53e5\u5c06\u5176\u4ece\u6570\u636e\u5e93\u4e2d\u5220\u9664\u3002<\/p>\n
        \u5b9e\u9645\u4e0a\u6839\u672c\u4e0d\u9700\u8981\u68c0\u7d22\u5b9e\u4f53\u3002\u60a8\u53ef\u4ee5\u4f7f\u7528\u6240\u8c13\u7684\u5b58\u6839\u6765\u8868\u793a\u8981\u5220\u9664\u7684\u5b9e\u4f53\u3002\u5b58\u6839\u662f\u4ec5\u5206\u914d\u4e86\u5176\u952e\u503c\u7684\u5b9e\u4f53\u3002\u5047\u8bbe\u60a8\u5df2\u7ecf\u4fee\u6539\u4e86\u6b64\u9875\u9762\uff0c\u4ee5\u4f7f\u7528\u8868\u793a\u952e\u503c\u7684\u53d7\u7ea6\u675f\u8def\u7531\u53c2\u6570\uff0c\u800c\u4e0d\u662f\u53ef\u4e3a null \u7684\u5904\u7406\u7a0b\u5e8f\u53c2\u6570\u3002\u4e0b\u4e00\u4e2a\u6e05\u5355\u663e\u793a\u4e86\u5982\u4f55\u4f7f\u7528\u5b58\u6839\u6765\u8868\u793a\u8981\u5728 OnPostAsync \u65b9\u6cd5\u4e2d\u5220\u9664\u7684\u5b9e\u4f53\u3002<\/p>\n
        \u793a\u4f8b 8.34 \u5220\u9664\u7531 stub \u8868\u793a\u7684\u5b9e\u4f53<\/p>\n
        public async Task<IActionResult> OnPostAsync()\n{\n    var property = new Property { Id = Id };     \u2776\n    _context.Remove(property );                  \u2777\n    await _context.SaveChangesAsync();\n\n    return RedirectToPage(".\/Index");\n}<\/code><\/pre>\n
        \u2776 \u521b\u5efa\u4e00\u4e2a\u5b58\u6839\uff0c\u4ec5\u5206\u914d\u5176 key \u503c\u3002
        \n\u2777 \u5c06\u5b58\u6839\u4f20\u9012\u7ed9 DbContext.Remove \u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u5c06\u5b9e\u4f53\u6807\u8bb0\u4e3a Deleted\u3002<\/p>\n
        \u91c7\u7528\u8fd9\u79cd\u65b9\u6cd5\uff0c\u60a8\u53ef\u4ee5\u663e\u8457\u964d\u4f4e\u4ee3\u7801\u7684\u590d\u6742\u6027\uff0c\u5e76\u5c06\u5b9e\u73b0\u76ee\u6807\u6240\u9700\u7684\u6570\u636e\u5e93\u8c03\u7528\u6b21\u6570\u51cf\u534a\u3002\u8bf7\u6ce8\u610f\uff0c\u60a8\u8fd8\u4f7f\u7528\u4e86 DbContext.Remove \u65b9\u6cd5\uff0c\u800c\u4e0d\u662f\u57fa\u67b6\u751f\u6210\u7684 DbSet.Remove \u65b9\u6cd5\u3002\u4e0e DbContext Add \u548c Update \u65b9\u6cd5\u4e00\u6837\uff0cRemove \u65b9\u6cd5\u662f EF Core \u7684\u65b0\u589e\u529f\u80fd\uff0c\u53ef\u5e2e\u52a9\u4f60\u51cf\u5c11\u4ee3\u7801\u3002<\/p>\n
        \u5220\u9664\u5b9e\u4f53\u65f6\uff0c\u6240\u6709\u4f9d\u8d56\u6570\u636e\u90fd\u5c06\u4e22\u5931\u6216\u5b64\u7acb\u3002\u6839\u636e\u5916\u952e\u7684\u8bbe\u7f6e\u65b9\u5f0f\uff0c\u5220\u9664\u4f5c\u5c06\u7ea7\u8054\u5230\u6240\u6709\u4f9d\u8d56\u6570\u636e\uff0c\u5e76\u4e14\u8fd8\u4f1a\u5220\u9664\u8be5\u6570\u636e\uff0c\u6216\u8005\u5c06\u5176\u5916\u952e\u503c\u66f4\u65b0\u4e3a null\uff0c\u4ece\u800c\u5bfc\u81f4\u5b64\u7acb\u6570\u636e\u3002\u5982\u679c\u4f9d\u8d56\u6570\u636e\u662f\u4e1a\u52a1\u5173\u952e\u578b\u6570\u636e\uff08\u5982 orders\uff09\uff0c\u5219\u4e0d\u9700\u8981\u8fd9\u6837\u505a\u3002\u60a8\u663e\u7136\u5e0c\u671b\u4fdd\u7559\u6709\u5173\u4f4f\u5bbf\u9884\u8ba2\u7684\u5386\u53f2\u6570\u636e\uff0c\u4f8b\u5982\uff0c\u5c3d\u7ba1\u5b83\u5df2\u88ab\u63a8\u5e73\u3002\u5982\u679c\u5b83\u88ab\u610f\u5916\u5220\u9664\uff0c\u60a8\u751a\u81f3\u53ef\u80fd\u9700\u8981\u6062\u590d\u5b83\u3002\u56e0\u6b64\uff0c\u60a8\u5c06\u66f4\u9891\u7e41\u5730\u4f7f\u7528\u8f6f\u5220\u9664\uff0c\u5373\u4ee5\u67d0\u79cd\u65b9\u5f0f\u5c06\u8bb0\u5f55\u6807\u8bb0\u4e3a\u5df2\u5220\u9664\uff0c\u800c\u4e0d\u662f\u5b8c\u5168\u5220\u9664\u8bb0\u5f55\uff0c\u8fd9\u5c31\u662f DbContext.Remove \u65b9\u6cd5\u7684\u7ed3\u679c\u3002\u5728\u672c\u7ae0\u7684\u6700\u540e\u4e00\u8282\u4e2d\uff0c\u60a8\u5c06\u5411 Property \u7c7b\u6dfb\u52a0\u4e00\u4e2a\u65b0\u5c5e\u6027\uff0c\u8be5\u5c5e\u6027\u8868\u793a\u5b9e\u4f53\u6807\u8bb0\u4e3a\u5df2\u5220\u9664\u7684\u65e5\u671f\u548c\u65f6\u95f4\u3002\u60a8\u5c06\u6dfb\u52a0\u65b0\u7684\u8fc1\u79fb\u4ee5\u66f4\u65b0\u6570\u636e\u5e93\u67b6\u6784\uff0c\u7136\u540e\u4fee\u6539 Delete \u9875\u9762\u4ee5\u9002\u5e94\u60a8\u4fee\u8ba2\u540e\u7684\u5220\u9664\u7ba1\u7406\u7b56\u7565\u3002<\/p>\n
        \u7b2c\u4e00\u6b65\u662f\u5c06\u53ef\u4e3a null \u7684 DateTime \u5c5e\u6027\u6dfb\u52a0\u5230 Property \u7c7b\uff1a<\/p>\n
        public DateTime? Deleted { get; set; }<\/code><\/pre>\n
        \u4e3a\u6b64\uff0c\u6211\u901a\u5e38\u4f7f\u7528 DateTime \u800c\u4e0d\u662f bool\uff0c\u56e0\u4e3a\u4e0d\u53ef\u907f\u514d\u5730\u4f1a\u6709\u4eba\u8be2\u95ee\u9879\u76ee\u4f55\u65f6\u88ab\u5220\u9664\u3002\u5728\u6ca1\u6709\u66f4\u590d\u6742\u7684\u65e5\u5fd7\u8bb0\u5f55\u7684\u60c5\u51b5\u4e0b\uff0c\u81f3\u5c11\u8fd9\u53ef\u4ee5\u5e2e\u52a9\u6211\u56de\u7b54\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n
        \u6211\u5c06\u501f\u6b64\u673a\u4f1a\u5f3a\u8c03\u5173\u4e8e\u8fc7\u5ea6\u53d1\u5e03\u653b\u51fb\u7684\u89c2\u70b9\u3002\u60a8\u521a\u521a\u5411\u7c7b\u4e2d\u6dfb\u52a0\u4e86\u4e00\u4e2a\u4e0d\u5e0c\u671b\u7528\u6237\u76f4\u63a5\u8bbe\u7f6e\u7684\u65b0\u5c5e\u6027\u3002\u5982\u679c\u5141\u8bb8\u6a21\u578b\u7ed1\u5b9a\u5668\u76f4\u63a5\u7ed1\u5b9a\u5230\u7c7b\u7684\u5b9e\u4f8b\uff0c\u5219\u4f1a\u5411\u7528\u6237\u516c\u5f00\u6b64\u5c5e\u6027\u3002\u901a\u8fc7\u4ec5\u5c06\u5355\u4e2a\u5c5e\u6027\u6307\u5b9a\u4e3a\u7ed1\u5b9a\u76ee\u6807\uff0c\u53ef\u4ee5\u9632\u6b62\u7528\u6237\u8bbe\u7f6e Deleted \u5c5e\u6027\u7684\u503c\u3002<\/p>\n
        \u6dfb\u52a0 Deleted \u5c5e\u6027\u540e\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528\u5305\u7ba1\u7406\u5668\u63a7\u5236\u53f0\u6216\u547d\u4ee4\u884c\u6dfb\u52a0\u65b0\u7684\u8fc1\u79fb\uff0c\u8fd9\u5c06\u68c0\u6d4b\u60a8\u5bf9\u6a21\u578b\u6240\u505a\u7684\u66f4\u6539\uff0c\u5e76\u901a\u8fc7\u76f8\u5e94\u5730\u4fee\u6539\u6570\u636e\u5e93\u67b6\u6784\u6765\u53cd\u6620\u8fd9\u4e9b\u66f4\u6539\u3002Powershell \u548c\u547d\u4ee4\u884c\u9009\u9879\u90fd\u663e\u793a\u5728\u4e0b\u9762\u7684\u6e05\u5355\u4e2d\u3002<\/p>\n
        \u5217\u8868 8.35 \u6dfb\u52a0\u8fc1\u79fb<\/p>\n
        [Powershell]                                      \u2776\nadd-migration AddedDeleteToProperty               \u2776\n[CLI]                                             \u2777\ndotnet ef migrations add AddedDeleteToProperty    \u2777<\/code><\/pre>\n
        \u2776 \u8981\u4ece Visual Studio \u7684\u5305\u7ba1\u7406\u5668\u63a7\u5236\u53f0\u4e2d\u6267\u884c\u7684 Powershell \u547d\u4ee4
        \n\u2777 \u8981\u4ece\u5305\u542b csproj \u6587\u4ef6\u7684\u76ee\u5f55\u4e2d\u7684\u547d\u4ee4\u63d0\u793a\u7b26\u6267\u884c\u7684 CLI \u547d\u4ee4<\/p>\n
        \u6267\u884c\u540e\uff0c\u60a8\u53ef\u4ee5\u68c0\u67e5\u8fc1\u79fb\u4ee3\u7801\u4e2d\u7684 Up \u65b9\u6cd5\uff0c\u4ee5\u786e\u4fdd\u5b83\u5c06\u6dfb\u52a0\u53ef\u4e3a null \u7684 Delete \u5217\u3002\u5728 SQLite \u4e2d\uff0c\u8fd9\u5c06\u662f\u4e00\u4e2a TEXT \u7c7b\u578b\u3002<\/p>\n
        \u6e05\u5355 8.36 \u65b0\u8fc1\u79fb\u7684 Up \u65b9\u6cd5<\/p>\n
        protected override void Up(MigrationBuilder migrationBuilder)\n{\n    migrationBuilder.AddColumn<DateTime>(\n        name: "Deleted",\n        table: "Properties",\n        type: "TEXT",\n        nullable: true);\n}<\/code><\/pre>\n
        \u73b0\u5728\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u4e4b\u4e00\u5e94\u7528\u8fc1\u79fb\uff1a<\/p>\n
        [Powershell]\nupdate-database\n[CLI]\ndotnet ef database update<\/code><\/pre>\n
        \u5b8c\u6210\u540e\uff0c\u5411 IPropertyService \u63a5\u53e3\u6dfb\u52a0\u65b0\u65b9\u6cd5\uff1a<\/p>\n
        Task DeleteAsync(int id);<\/code><\/pre>\n
        \u7136\u540e\u5411 PropertyService \u7c7b\u6dfb\u52a0\u4e00\u4e2a\u5b9e\u73b0\u3002<\/p>\n
        \u5217\u8868 8.37 Delete \u65b9\u6cd5\u5b9e\u73b0<\/p>\n
        public async Task DeleteAsync(int id)\n{\n    var property = new Property { Id = id, Deleted = DateTime.Now };      \u2776\n    _context.Attach(property).Property(p => p.Deleted).IsModified = true; \u2777\n    await _context.SaveChangesAsync();                                    \u2778\n}<\/code><\/pre>\n
        \u2776 \u521b\u5efa\u4e00\u4e2a\u5b58\u6839\u6765\u8868\u793a\u8981\u4fee\u6539\u7684\u9879\u3002
        \n\u2777 \u5c06\u5b9e\u4f53\u9644\u52a0\u5230\u4e0a\u4e0b\u6587\uff0c\u5e76\u6307\u5b9a\u5e94\u4fee\u6539\u7684\u5c5e\u6027\u3002
        \n\u2778 \u63d0\u4ea4\u66f4\u6539\u3002<\/p>\n
        \u6b64\u65b9\u6cd5\u63d0\u4f9b\u4e86\u53e6\u4e00\u4e2a stub \u6709\u7528\u7684\u793a\u4f8b\u3002\u60a8\u53ea\u60f3\u66f4\u65b0\u6b64\u5b9e\u4f53\u7684\u6570\u636e\u5e93\u4e2d\u7684 Deleted \u5217\u3002\u5982\u679c\u5c06\u6574\u4e2a\u5b9e\u4f53\u4f20\u9012\u7ed9 Update \u65b9\u6cd5\uff0c\u5219\u6240\u6709\u5c5e\u6027\u90fd\u5305\u542b\u5728\u751f\u6210\u7684 SQL UPDATE \u8bed\u53e5\u4e2d\u3002\u4e3a\u907f\u514d\u8fd9\u79cd\u60c5\u51b5\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 Attach \u544a\u8bc9\u4e0a\u4e0b\u6587\u5f00\u59cb\u8ddf\u8e2a\u60a8\u7684\u5b9e\u4f53\uff0c\u5e76\u5c06\u5176\u72b6\u6001\u8bbe\u7f6e\u4e3a Unchanged\u3002\u7136\u540e\uff0c\u5c06 Deleted \u5c5e\u6027\u663e\u5f0f\u8bbe\u7f6e\u4e3a modified\u3002\u5c06\u5355\u4e2a\u5c5e\u6027\u8bbe\u7f6e\u4e3a\u5df2\u4fee\u6539\u65f6\uff0cUPDATE \u8bed\u53e5\u4e2d\u4ec5\u5305\u542b\u8fd9\u4e9b\u5c5e\u6027\u3002\u60a8\u53ef\u4ee5\u901a\u8fc7\u5c06 DeleteModel \u4e2d\u6ce8\u5165\u7684\u4e0a\u4e0b\u6587\u66ff\u6362\u4e3a IPropertyService \u6765\u5229\u7528\u6b64\u65b9\u6cd5\u3002<\/p>\n
        \u5217\u8868 8.38 \u4fee\u6539\u540e\u7684 DeleteModel \u4f9d\u8d56\u4e8e IPropertyService<\/p>\n
        public class DeleteModel : PageModel\n{\n    private readonly IPropertyService _propertyService;      \u2776\n\n    public DeleteModel(IPropertyService propertyService)     \u2776\n    {                                                        \u2776\n        _propertyService = propertyService;                  \u2776\n    }                                                        \u2776\n\n    public Property Property { get; set; }                   \u2777\n\n    [BindProperty(SupportsGet = true)]                       \u2778\n    public int Id { get; set; }                              \u2778\n\n    public async Task<IActionResult> OnGetAsync()            \u2779\n    {                                                        \u2779\n        Property = await _propertyService.FindAsync(Id);     \u2779\n\n        if (Property == null)                                \u2779\n        {                                                    \u2779\n            return NotFound();                               \u2779\n        }                                                    \u2779\n        return Page();                                       \u2779\n    }                                                        \u2779\n\n    public async Task<IActionResult> OnPostAsync()           \u277a\n    {                                                        \u277a\n        await _propertyService.DeleteAsync(Id);              \u277a\n        return RedirectToPage(".\/Index");                    \u277a\n    }                                                        \u277a\n}<\/code><\/pre>\n
        \u2776 \u6ce8\u5165\u7684\u4e0a\u4e0b\u6587\u5c06\u66ff\u6362\u4e3a IPropertyService\u3002
        \n\u2777 \u4ece Property \u5c5e\u6027\u4e2d\u5220\u9664\u4e0d\u5fc5\u8981\u7684 BindProperty \u5c5e\u6027\u3002
        \n\u2778 \u4e3a key \u503c\u6dfb\u52a0 bound \u5c5e\u6027\uff0c\u66ff\u6362\u5904\u7406\u7a0b\u5e8f\u53c2\u6570\u3002
        \n\u2779 \u5220\u9664\u5bf9 key \u503c\u7684 null \u68c0\u67e5\uff0c\u56e0\u4e3a\u60a8\u5c06\u6539\u7528\u8def\u7531\u7ea6\u675f\u3002
        \n\u277a \u4f7f\u7528\u670d\u52a1\u201c\u5220\u9664\u201d\u5b9e\u4f53\u3002<\/p>\n
        \u4e0e \u201c\u7f16\u8f91 \u201d\u9875\u4e00\u6837\uff0c\u5982\u679c URL \u4e2d\u5305\u542b\u6574\u6570\u503c\uff0c\u5219\u53ea\u5e0c\u671b\u8bbf\u95ee \u201c\u5220\u9664 \u201d\u9875\uff0c\u56e0\u6b64\u8f6c\u5230 Delete.cshtml \u5e76\u6dfb\u52a0\u8def\u7531\u7ea6\u675f\u4f5c\u4e3a\u8def\u7531\u6a21\u677f\u7684\u4e00\u90e8\u5206\uff1a<\/p>\n
        @page "{id:int}"<\/code><\/pre>\n
        \u5728\u6d4b\u8bd5\u4e4b\u524d\uff0c\u8fd8\u6709\u4e24\u4ef6\u4e8b\u8981\u505a\u3002\u7b2c\u4e00\u79cd\u65b9\u6cd5\u662f\u66f4\u6539 PropertyService \u4e2d\u7684 GetAllAsync \u65b9\u6cd5\uff0c\u4ee5\u6392\u9664\u5177\u6709\u5206\u914d\u7ed9\u5176 Deleted \u5c5e\u6027\u7684\u503c\u7684\u5c5e\u6027\u3002<\/p>\n
        \u6e05\u5355 8.39 \u4ece\u7ed3\u679c\u96c6\u4e2d\u6392\u9664\u5df2\u5220\u9664\u7684\u5c5e\u6027<\/p>\n
        public async Task<List<Property>> GetAllAsync() =>\n    await _context.Properties\n    .Where(p => !p.Deleted.HasValue)\n    .Include(x => x.City)\n    .ToListAsync();<\/code><\/pre>\n
        \u7136\u540e\uff0c\u60a8\u66f4\u6539 PropertyManager\\Index.cshtml.cs \u6587\u4ef6\u4e2d\u7684 IndexModel \u7c7b\uff0c\u4ee5\u4ece\u5c5e\u4e8e IPropertyService \u800c\u4e0d\u662f\u4e0a\u4e0b\u6587\uff0c\u4ee5\u4fbf\u60a8\u53ef\u4ee5\u4f7f\u7528\u65b0\u65b9\u6cd5\u586b\u5145\u9875\u9762\u3002<\/p>\n
        \u6e05\u5355 8.40 \u4fee\u6539\u540e\u7684 PropertyManager IndexModel<\/p>\n
        public class IndexModel : PageModel\n{\n    private readonly IPropertyService _propertyService;\n\n    public IndexModel(IPropertyService propertyService)\n    {\n        _propertyService = propertyService;\n    }\n\n    public IList<Property> Property { get;set; }\n\n    public async Task OnGetAsync()\n    {\n        Property = await _propertyService.GetAllAsync();\n    }\n}<\/code><\/pre>\n
        \u73b0\u5728\u8fd0\u884c\u5e94\u7528\u7a0b\u5e8f\uff0c\u5e76\u5bfc\u822a\u5230 \/property-manager\u3002\u89c2\u5bdf\u5217\u8868\u4e2d\u7684\u7b2c\u4e00\u4e2a\u5c5e\u6027\u3002\u5982\u679c\u60a8\u4f7f\u7528\u7684\u662f\u4e0a\u4e00\u7ae0\u4e0b\u8f7d\u4e2d\u63d0\u4f9b\u7684\u79cd\u5b50\u6570\u636e\uff0c\u5219\u5217\u8868\u4e2d\u7684\u7b2c\u4e00\u4e2a\u5c5e\u6027\u5e94\u8be5\u662f Hotel Paris\u3002\u70b9\u51fb Delete \u94fe\u63a5\u5c06\u5e26\u60a8\u8fdb\u5165 Delete \u9875\u9762\uff0c\u8be5\u9875\u9762\u8981\u6c42\u60a8\u786e\u8ba4\u662f\u5426\u8981\u5220\u9664\u6b64\u9879\u76ee\uff08\u56fe 8.16\uff09\u3002<\/p>\n
        <\/p>\n
        \u56fe 8.16 \u201c\u5220\u9664\u201d\u9875\u9762<\/p>\n
        \u5355\u51fb Delete \u6309\u94ae\uff0c\u7136\u540e\u89c2\u5bdf Hotel Paris \u4e0d\u518d\u5728\u5217\u8868\u4e2d\u3002\u4f5c\u4e3a\u6700\u540e\u7684\u68c0\u67e5\uff0c\u4f7f\u7528\u60a8\u719f\u6089\u7684\u4efb\u4f55\u6570\u636e\u5e93\u5de5\u5177\u67e5\u770b Properties \u8868\u4e2d\u7684\u6570\u636e\uff0c\u4ee5\u786e\u8ba4\u76f8\u5173\u8bb0\u5f55\u4ecd\u7136\u5b58\u5728 \u2014 \u5c3d\u7ba1\u73b0\u5728 Deleted \u5217\u4e2d\u6709\u4e00\u4e2a\u503c\uff08\u56fe 8.17\uff09\u3002<\/p>\n
        <\/p>\n
        \u56fe 8.17 \u6570\u636e\u5e93\u89c6\u56fe\u663e\u793a \u201cdeleted\u201d \u8bb0\u5f55\u4ecd\u7136\u5b58\u5728\u3002<\/p>\n
        \u8fd9\u662f\u4e00\u4e2a\u5f88\u957f\u7684\u7ae0\u8282\uff0c\u4f46\u6211\u4eec\u53ea\u771f\u6b63\u89e6\u53ca\u4e86 EF Core \u53ef\u4ee5\u505a\u4ec0\u4e48\u7684\u76ae\u6bdb\u3002\u6211\u5c06\u518d\u6b21\u63a8\u8350 Jon P. Smith \u7684 Entity Framework Core in Action\uff08\u7b2c 2 \u7248;http:\/\/mng.bz\/WMeg\uff09\u4f5c\u4e3a\u4e86\u89e3\u6709\u5173\u5982\u4f55\u4f7f\u7528<\/a> EF Core \u4ee5\u53ca\u5b98\u65b9\u6587\u6863 \uff08https:\/\/docs.microsoft.com\/en-us\/ef\/<\/a>\uff09 \u7684\u66f4\u591a\u4fe1\u606f\u7684\u7edd\u4f73\u8d44\u6e90\u3002<\/p>\n
        \u60a8\u5df2\u7ecf\u5c06\u5e94\u7528\u7a0b\u5e8f\u5411\u524d\u63a8\u8fdb\uff0c\u56e0\u4e3a\u5b83\u73b0\u5728\u53ef\u4ee5\u4e0e\u6570\u636e\u5e93\u4ea4\u4e92\u3002\u4f46\u662f\uff0c\u5982\u679c\u8bbf\u95ee\u8be5\u7ad9\u70b9\u7684\u4efb\u4f55\u4eba\u77e5\u9053 CRUD \u9875\u9762\u7684 URL\uff0c\u5c31\u53ef\u4ee5\u6dfb\u52a0\u548c\u4fee\u6539\u6570\u636e\u3002\u5728\u63a5\u4e0b\u6765\u7684\u4e24\u7ae0\u4e2d\uff0c\u6211\u4eec\u5c06\u4ecb\u7ecd\u5982\u4f55\u5bf9\u7528\u6237\u8fdb\u884c\u8eab\u4efd\u9a8c\u8bc1\uff0c\u4ee5\u4fbf\u60a8\u4e86\u89e3\u4ed6\u4eec\u662f\u8c01\uff0c\u7136\u540e\u4fdd\u62a4\u672a\u7ecf\u6388\u6743\u7684\u7528\u6237\u5bf9\u8fd9\u4e9b\u9875\u9762\u7684\u8bbf\u95ee\u3002<\/p>\n
        \u603b\u7ed3<\/h2>\n
        Entity Framework Core \u662f Microsoft \u63d0\u4f9b\u7684\u4e00\u79cd\u5bf9\u8c61\u5173\u7cfb\u6620\u5c04 \uff08ORM\uff09 \u5de5\u5177\uff0c\u5b83\u5145\u5f53\u63d2\u5165\u5f0f\u6570\u636e\u5c42\uff0c\u62bd\u8c61\u51fa\u4f7f\u7528\u5173\u7cfb\u6570\u636e\u5e93\u6240\u9700\u7684\u6837\u677f\u4ee3\u7801\u3002
        \n\u4f7f\u7528 EF Core \u7684\u4e3b\u8981\u5165\u53e3\u70b9\u662f\u901a\u8fc7\u4e0a\u4e0b\u6587\uff0c\u5373\u6d3e\u751f\u81ea DbContext \u7684\u5bf9\u8c61\u3002
        \nEF Core \u4e0a\u4e0b\u6587\u8ddf\u8e2a\u5bf9\u8c61\u5e76\u6839\u636e\u5176\u72b6\u6001\u751f\u6210 SQL\u3002
        \n\u5b9e\u4f53\u901a\u8fc7 DbSet \u5bf9\u8c61\u6620\u5c04\u5230\u6570\u636e\u5e93\u8868\u3002
        \nEF Core \u5c06 LINQ \u67e5\u8be2\u8f6c\u6362\u4e3a SQL\uff0c\u7136\u540e\u9488\u5bf9\u6570\u636e\u5e93\u6267\u884c SQL\u3002
        \n\u7ea6\u5b9a\u9a71\u52a8\u5bf9\u8c61\u548c\u6570\u636e\u5e93\u4e4b\u95f4\u7684 EF Core \u6620\u5c04\u3002
        \n\u60a8\u53ef\u4ee5\u4f7f\u7528 configuration \u81ea\u5b9a\u4e49\u6620\u5c04\u3002
        \nEF Core \u8fc1\u79fb\u4f7f\u4f60\u80fd\u591f\u4f7f\u6a21\u578b\u548c\u6570\u636e\u5e93\u67b6\u6784\u5f7c\u6b64\u4fdd\u6301\u540c\u6b65\u3002
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