{"id":194975,"date":"2024-11-13T11:09:22","date_gmt":"2024-11-13T03:09:22","guid":{"rendered":"https:\/\/server.hk\/cnblog\/194975\/"},"modified":"2024-11-13T11:09:23","modified_gmt":"2024-11-13T03:09:23","slug":"%e7%94%a8%e6%88%b6%e6%ac%8a%e9%99%90%e7%ae%a1%e7%90%86%e4%b9%8b%e7%94%a8linq%e5%8e%bb%e9%99%a4%e9%87%8d%e8%a4%87%e8%8f%9c%e5%96%ae%e9%a0%85%e7%9a%84%e6%93%8d%e4%bd%9c%e8%a9%b3%e8%a7%a3","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/194975\/","title":{"rendered":"\u7528\u6236\u6b0a\u9650\u7ba1\u7406\u4e4b\u7528LINQ\u53bb\u9664\u91cd\u8907\u83dc\u55ae\u9805\u7684\u64cd\u4f5c\u8a73\u89e3"},"content":{"rendered":"

\u7528\u6236\u6b0a\u9650\u7ba1\u7406\u4e4b\u7528LINQ\u53bb\u9664\u91cd\u8907\u83dc\u55ae\u9805\u7684\u64cd\u4f5c\u8a73\u89e3<\/h1>\n

\u5728\u73fe\u4eca\u7684\u61c9\u7528\u7a0b\u5f0f\u958b\u767c\u4e2d\uff0c\u7528\u6236\u6b0a\u9650\u7ba1\u7406\u662f\u4e00\u500b\u81f3\u95dc\u91cd\u8981\u7684\u90e8\u5206\u3002\u96a8\u8457\u7cfb\u7d71\u7684\u8907\u96dc\u6027\u589e\u52a0\uff0c\u5982\u4f55\u6709\u6548\u5730\u7ba1\u7406\u7528\u6236\u7684\u6b0a\u9650\uff0c\u7279\u5225\u662f\u5728\u83dc\u55ae\u9805\u7684\u986f\u793a\u4e0a\uff0c\u6210\u70ba\u4e86\u958b\u767c\u8005\u9700\u8981\u9762\u5c0d\u7684\u6311\u6230\u4e4b\u4e00\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5982\u4f55\u4f7f\u7528LINQ\uff08Language Integrated Query\uff09\u4f86\u53bb\u9664\u91cd\u8907\u7684\u83dc\u55ae\u9805\uff0c\u5f9e\u800c\u63d0\u5347\u7528\u6236\u9ad4\u9a57\u548c\u7cfb\u7d71\u7684\u6574\u9ad4\u6027\u80fd\u3002<\/p>\n

\u70ba\u4f55\u9700\u8981\u53bb\u9664\u91cd\u8907\u83dc\u55ae\u9805<\/h2>\n

\u5728\u8a31\u591a\u61c9\u7528\u7a0b\u5f0f\u4e2d\uff0c\u83dc\u55ae\u9805\u7684\u91cd\u8907\u986f\u793a\u6703\u5c0e\u81f4\u7528\u6236\u6df7\u6dc6\uff0c\u5f71\u97ff\u64cd\u4f5c\u7684\u6d41\u66a2\u6027\u3002\u91cd\u8907\u7684\u83dc\u55ae\u9805\u4e0d\u50c5\u6d6a\u8cbb\u4e86\u754c\u9762\u7a7a\u9593\uff0c\u9084\u53ef\u80fd\u4f7f\u5f97\u7528\u6236\u5728\u9078\u64c7\u6642\u7522\u751f\u56f0\u60d1\u3002\u56e0\u6b64\uff0c\u53bb\u9664\u91cd\u8907\u83dc\u55ae\u9805\u662f\u63d0\u5347\u7528\u6236\u9ad4\u9a57\u7684\u91cd\u8981\u6b65\u9a5f\u3002<\/p>\n

LINQ\u7c21\u4ecb<\/h2>\n

LINQ\u662f\u4e00\u7a2e\u7528\u65bc.NET\u8a9e\u8a00\u7684\u67e5\u8a62\u8a9e\u8a00\uff0c\u5b83\u5141\u8a31\u958b\u767c\u8005\u4ee5\u66f4\u7c21\u6f54\u7684\u65b9\u5f0f\u67e5\u8a62\u6578\u64da\u3002LINQ\u7684\u8a9e\u6cd5\u7c21\u55ae\u6613\u61c2\uff0c\u4e26\u4e14\u80fd\u5920\u8207\u591a\u7a2e\u6578\u64da\u6e90\uff08\u5982\u6578\u7d44\u3001\u96c6\u5408\u3001\u6578\u64da\u5eab\u7b49\uff09\u9032\u884c\u4ea4\u4e92\u3002\u4f7f\u7528LINQ\uff0c\u6211\u5011\u53ef\u4ee5\u8f15\u9b06\u5730\u5c0d\u6578\u64da\u9032\u884c\u904e\u6ffe\u3001\u6392\u5e8f\u548c\u5206\u7d44\u7b49\u64cd\u4f5c\u3002<\/p>\n

\u4f7f\u7528LINQ\u53bb\u9664\u91cd\u8907\u83dc\u55ae\u9805\u7684\u6b65\u9a5f<\/h2>\n

\u4ee5\u4e0b\u662f\u4f7f\u7528LINQ\u53bb\u9664\u91cd\u8907\u83dc\u55ae\u9805\u7684\u5177\u9ad4\u6b65\u9a5f\uff1a<\/p>\n

1. \u6e96\u5099\u6578\u64da\u6e90<\/h3>\n

\u9996\u5148\uff0c\u6211\u5011\u9700\u8981\u4e00\u500b\u5305\u542b\u83dc\u55ae\u9805\u7684\u6578\u64da\u6e90\u3002\u9019\u88e1\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u83dc\u55ae\u9805\u7684\u5217\u8868\uff0c\u6bcf\u500b\u83dc\u55ae\u9805\u90fd\u6709\u4e00\u500b\u540d\u7a31\u548c\u4e00\u500bID\u3002<\/p>\n

List menuItems = new List\n{\n    new MenuItem { Id = 1, Name = \"\u9996\u9801\" },\n    new MenuItem { Id = 2, Name = \"\u95dc\u65bc\u6211\u5011\" },\n    new MenuItem { Id = 3, Name = \"\u670d\u52d9\" },\n    new MenuItem { Id = 1, Name = \"\u9996\u9801\" }, \/\/ \u91cd\u8907\u9805\n    new MenuItem { Id = 4, Name = \"\u806f\u7e6b\u6211\u5011\" }\n};<\/code><\/pre>\n
2. \u4f7f\u7528LINQ\u53bb\u9664\u91cd\u8907\u9805<\/h3>\n
\u63a5\u4e0b\u4f86\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528LINQ\u7684Distinct\u65b9\u6cd5\u4f86\u53bb\u9664\u91cd\u8907\u7684\u83dc\u55ae\u9805\u3002\u9019\u88e1\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0cDistinct\u65b9\u6cd5\u9700\u8981\u4e00\u500b\u81ea\u5b9a\u7fa9\u7684\u6bd4\u8f03\u5668\u4f86\u5224\u65b7\u83dc\u55ae\u9805\u662f\u5426\u76f8\u540c\u3002<\/p>\n
var distinctMenuItems = menuItems\n    .GroupBy(item => item.Id)\n    .Select(group => group.First())\n    .ToList();<\/code><\/pre>\n
\u5728\u9019\u6bb5\u4ee3\u78bc\u4e2d\uff0c\u6211\u5011\u9996\u5148\u4f7f\u7528GroupBy\u65b9\u6cd5\u6839\u64daID\u5c07\u83dc\u55ae\u9805\u5206\u7d44\uff0c\u7136\u5f8c\u9078\u64c7\u6bcf\u7d44\u7684\u7b2c\u4e00\u500b\u9805\u76ee\uff0c\u5f9e\u800c\u9054\u5230\u53bb\u9664\u91cd\u8907\u7684\u76ee\u7684\u3002<\/p>\n
3. \u986f\u793a\u7d50\u679c<\/h3>\n
\u6700\u5f8c\uff0c\u6211\u5011\u53ef\u4ee5\u5c07\u53bb\u9664\u91cd\u8907\u7684\u83dc\u55ae\u9805\u986f\u793a\u51fa\u4f86\uff1a<\/p>\n
foreach (var item in distinctMenuItems)\n{\n    Console.WriteLine($\"ID: {item.Id}, \u540d\u7a31: {item.Name}\");\n}<\/code><\/pre>\n
\u9019\u6a23\uff0c\u6211\u5011\u5c31\u6210\u529f\u5730\u53bb\u9664\u4e86\u91cd\u8907\u7684\u83dc\u55ae\u9805\uff0c\u4e26\u4e14\u5c07\u7d50\u679c\u8f38\u51fa\u5230\u63a7\u5236\u53f0\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u901a\u904e\u4f7f\u7528LINQ\uff0c\u6211\u5011\u53ef\u4ee5\u8f15\u9b06\u5730\u53bb\u9664\u91cd\u8907\u7684\u83dc\u55ae\u9805\uff0c\u5f9e\u800c\u63d0\u5347\u7528\u6236\u7684\u64cd\u4f5c\u9ad4\u9a57\u3002\u9019\u4e0d\u50c5\u80fd\u5920\u4f7f\u754c\u9762\u66f4\u52a0\u6574\u6f54\uff0c\u9084\u80fd\u63d0\u9ad8\u7cfb\u7d71\u7684\u6027\u80fd\u3002\u5c0d\u65bc\u958b\u767c\u8005\u4f86\u8aaa\uff0c\u638c\u63e1LINQ\u7684\u4f7f\u7528\u6280\u5de7\u662f\u975e\u5e38\u91cd\u8981\u7684\uff0c\u9019\u5c07\u6709\u52a9\u65bc\u6211\u5011\u5728\u65e5\u5e38\u958b\u767c\u4e2d\u66f4\u9ad8\u6548\u5730\u8655\u7406\u6578\u64da\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 VPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u7528\u6236\u7684\u9700\u6c42\u3002\u7121\u8ad6\u662f \u9999\u6e2fVPS<\/a> \u9084\u662f\u5176\u4ed6\u985e\u578b\u7684 \u4f3a\u670d\u5668<\/a>\uff0c\u6211\u5011\u90fd\u80fd\u70ba\u60a8\u63d0\u4f9b\u7a69\u5b9a\u53ef\u9760\u7684\u670d\u52d9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u8a73\u89e3\u5982\u4f55\u4f7f\u7528LINQ\u5728\u7528\u6236\u6b0a\u9650\u7ba1\u7406\u4e2d\u53bb\u9664\u91cd\u8907\u83dc\u55ae\u9805\uff0c\u63d0\u5347\u7cfb\u7d71\u6548\u7387\u8207\u7528\u6236\u9ad4\u9a57\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-194975","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/194975","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=194975"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/194975\/revisions"}],"predecessor-version":[{"id":194976,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/194975\/revisions\/194976"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=194975"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=194975"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=194975"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}