{"id":3591,"date":"2025-04-20T18:49:20","date_gmt":"2025-04-20T10:49:20","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=3591"},"modified":"2025-04-20T18:49:20","modified_gmt":"2025-04-20T10:49:20","slug":"c-%e6%b3%9b%e5%9e%8b%ef%bc%88generics%ef%bc%89","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/04\/20\/c-%e6%b3%9b%e5%9e%8b%ef%bc%88generics%ef%bc%89\/","title":{"rendered":"C# \u6cdb\u578b\uff08Generics\uff09"},"content":{"rendered":"\n<p>\u4e0b\u9762\u662f\u4e00\u4e2a\u4ece<strong>\u4e13\u4e1a\u5f00\u53d1\u89d2\u5ea6\u51fa\u53d1\u3001\u5168\u9762\u6df1\u5165\u3001\u9644\u6743\u5a01\u94fe\u63a5<\/strong>\u7684\u3010C# \u6cdb\u578b\uff08Generic\uff09\u3011\u5b66\u4e60\u4e0e\u53c2\u8003\u6307\u5357\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">1\ufe0f\u20e3 \u4ec0\u4e48\u662f\u6cdb\u578b\uff1f\uff08Generics\uff09<\/h2>\n\n\n\n<p><strong>\u6cdb\u578b\uff08Generics\uff09<\/strong>\u662f .NET \u63d0\u4f9b\u7684\u4e00\u79cd<strong>\u7c7b\u578b\u53c2\u6570\u5316\u673a\u5236<\/strong>\uff0c\u5141\u8bb8\u7c7b\u3001\u63a5\u53e3\u3001\u65b9\u6cd5\u5728\u58f0\u660e\u65f6\u4e0d\u6307\u5b9a\u5177\u4f53\u6570\u636e\u7c7b\u578b\uff0c\u800c\u662f\u5728\u4f7f\u7528\u65f6\u6307\u5b9a\uff0c\u4ece\u800c\u63d0\u5347\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u7c7b\u578b\u5b89\u5168<\/strong><\/li>\n\n\n\n<li><strong>\u6027\u80fd<\/strong>\uff08\u907f\u514d\u88c5\u7bb1\/\u62c6\u7bb1\uff09<\/li>\n\n\n\n<li><strong>\u4ee3\u7801\u590d\u7528\u6027<\/strong><\/li>\n<\/ul>\n\n\n\n<p>\ud83d\udcd8 \u5b98\u65b9\u5b9a\u4e49\uff1ahttps:\/\/learn.microsoft.com\/en-us\/dotnet\/csharp\/programming-guide\/generics\/<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">2\ufe0f\u20e3 \u6cdb\u578b\u7684\u8bed\u6cd5\u7ed3\u6784<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">2.1 \u6cdb\u578b\u7c7b<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>public class GenericBox&lt;T&gt;\n{\n    public T Value { get; set; }\n}<\/code><\/pre>\n\n\n\n<p>\u4f7f\u7528\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var intBox = new GenericBox&lt;int&gt; { Value = 123 };\nvar strBox = new GenericBox&lt;string&gt; { Value = \"Hello\" };<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2.2 \u6cdb\u578b\u65b9\u6cd5<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>public T Max&lt;T&gt;(T a, T b) where T : IComparable&lt;T&gt;\n{\n    return a.CompareTo(b) &gt; 0 ? a : b;\n}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2.3 \u6cdb\u578b\u63a5\u53e3<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>public interface IRepository&lt;T&gt;\n{\n    void Add(T item);\n    T Get(int id);\n}<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">3\ufe0f\u20e3 \u6cdb\u578b\u7684\u4f18\u52bf<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u7279\u6027<\/th><th>\u4f18\u52bf\u8bf4\u660e<\/th><\/tr><\/thead><tbody><tr><td>\u7c7b\u578b\u5b89\u5168<\/td><td>\u7f16\u8bd1\u671f\u7c7b\u578b\u68c0\u67e5\uff0c\u907f\u514d\u8fd0\u884c\u65f6\u9519\u8bef<\/td><\/tr><tr><td>\u907f\u514d\u88c5\u7bb1\/\u62c6\u7bb1<\/td><td>\u63d0\u9ad8\u503c\u7c7b\u578b\u6027\u80fd\uff0c\u51cf\u5c11 GC \u538b\u529b<\/td><\/tr><tr><td>\u4ee3\u7801\u590d\u7528<\/td><td>\u4e00\u5957\u6cdb\u578b\u903b\u8f91\u53ef\u5904\u7406\u591a\u79cd\u6570\u636e\u7c7b\u578b<\/td><\/tr><tr><td>\u7075\u6d3b\u6027\u9ad8<\/td><td>\u53ef\u5b9a\u4e49\u7c7b\u578b\u7ea6\u675f\u3001\u7ee7\u627f\u5173\u7cfb<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">4\ufe0f\u20e3 \u7c7b\u578b\u53c2\u6570\u7ea6\u675f\uff08where\uff09<\/h2>\n\n\n\n<p>\u7ea6\u675f\u662f\u6cdb\u578b\u7cbe\u9ad3\uff0c\u63d0\u5347\u7c7b\u578b\u529f\u80fd\u4f7f\u7528\u80fd\u529b\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u7ea6\u675f<\/th><th>\u8bf4\u660e<\/th><th>\u793a\u4f8b<\/th><\/tr><\/thead><tbody><tr><td><code>where T : class<\/code><\/td><td>\u5f15\u7528\u7c7b\u578b<\/td><td>\u4e0d\u80fd\u4f20 int<\/td><\/tr><tr><td><code>where T : struct<\/code><\/td><td>\u503c\u7c7b\u578b<\/td><td>\u4e0d\u80fd\u4f20 string<\/td><\/tr><tr><td><code>where T : new()<\/code><\/td><td>\u5fc5\u987b\u6709\u65e0\u53c2\u6784\u9020\u51fd\u6570<\/td><td>\u53ef\u5728\u6cdb\u578b\u4e2d <code>new T()<\/code><\/td><\/tr><tr><td><code>where T : BaseClass<\/code><\/td><td>\u5fc5\u987b\u7ee7\u627f\u67d0\u7c7b<\/td><td>\u53ef\u8c03\u7528\u57fa\u7c7b\u65b9\u6cd5<\/td><\/tr><tr><td><code>where T : interface<\/code><\/td><td>\u5fc5\u987b\u5b9e\u73b0\u63a5\u53e3<\/td><td>\u5e38\u7528\u4e8e\u6cdb\u578b\u7b97\u6cd5<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\ud83d\udcd8 \u7ea6\u675f\u6587\u6863\uff1ahttps:\/\/learn.microsoft.com\/en-us\/dotnet\/csharp\/programming-guide\/generics\/constraints-on-type-parameters<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Factory&lt;T&gt; where T : new()\n{\n    public T Create() =&gt; new T();\n}<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">5\ufe0f\u20e3 \u6cdb\u578b\u4e0e\u96c6\u5408\u5e93\uff08\u6cdb\u578b\u96c6\u5408\uff09<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>List&lt;T><\/code>\u3001<code>Dictionary&lt;TKey, TValue><\/code> \u7b49\u96c6\u5408\u662f\u6cdb\u578b\u6700\u5178\u578b\u5e94\u7528<\/li>\n\n\n\n<li>\u5f3a\u7c7b\u578b\u3001\u9ad8\u6027\u80fd\u3001\u652f\u6301 LINQ \u64cd\u4f5c<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>List&lt;string&gt; names = new List&lt;string&gt; { \"Alice\", \"Bob\" };\nDictionary&lt;int, string&gt; map = new Dictionary&lt;int, string&gt;();<\/code><\/pre>\n\n\n\n<p>\ud83d\udcd8 \u6cdb\u578b\u96c6\u5408\u6c47\u603b\uff1ahttps:\/\/learn.microsoft.com\/en-us\/dotnet\/standard\/collections\/<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">6\ufe0f\u20e3 \u6cdb\u578b\u534f\u53d8\u4e0e\u9006\u53d8\uff08\u9ad8\u7ea7\uff09<\/h2>\n\n\n\n<p>\u7528\u4e8e\u63a5\u53e3\u4e0e\u59d4\u6258\u573a\u666f\uff0c\u5728\u6cdb\u578b\u63a5\u53e3\u4e4b\u95f4\u5141\u8bb8\u7c7b\u578b\u8f6c\u6362\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u7c7b\u578b<\/th><th>\u5173\u952e\u5b57<\/th><th>\u7528\u9014<\/th><\/tr><\/thead><tbody><tr><td>\u534f\u53d8<\/td><td><code>out<\/code><\/td><td>\u53ea\u8f93\u51fa\u65f6\u652f\u6301\u5b50\u7c7b\u5411\u7236\u7c7b\u8f6c\u6362<\/td><\/tr><tr><td>\u9006\u53d8<\/td><td><code>in<\/code><\/td><td>\u53ea\u8f93\u5165\u65f6\u652f\u6301\u7236\u7c7b\u5411\u5b50\u7c7b\u8f6c\u6362<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<pre class=\"wp-block-code\"><code>IEnumerable&lt;string&gt; strings = new List&lt;string&gt;();\nIEnumerable&lt;object&gt; objs = strings; \/\/ \u534f\u53d8<\/code><\/pre>\n\n\n\n<p>\ud83d\udcd8 \u534f\u53d8\u4e0e\u9006\u53d8\u8be6\u89e3\uff1ahttps:\/\/learn.microsoft.com\/en-us\/dotnet\/standard\/generics\/covariance-and-contravariance<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">7\ufe0f\u20e3 \u6cdb\u578b\u59d4\u6258<\/h2>\n\n\n\n<p>\u6cdb\u578b\u59d4\u6258\u53ef\u5b9a\u4e49\u8f93\u5165\u8f93\u51fa\u7c7b\u578b\u53c2\u6570\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public delegate T Transformer&lt;T&gt;(T input);\n\nTransformer&lt;int&gt; square = x =&gt; x * x;<\/code><\/pre>\n\n\n\n<p>.NET \u5185\u5efa\u7684\u6cdb\u578b\u59d4\u6258\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>Func&lt;T><\/code>\uff1a\u6709\u8fd4\u56de\u503c<\/li>\n\n\n\n<li><code>Action&lt;T><\/code>\uff1a\u65e0\u8fd4\u56de\u503c<\/li>\n\n\n\n<li><code>Predicate&lt;T><\/code>\uff1a\u8fd4\u56de\u5e03\u5c14\u503c<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">8\ufe0f\u20e3 \u6cdb\u578b\u4e0e\u53cd\u5c04\uff08\u9ad8\u7ea7\uff09<\/h2>\n\n\n\n<p>\u4f60\u53ef\u4ee5\u901a\u8fc7\u53cd\u5c04\u52a8\u6001\u521b\u5efa\u6cdb\u578b\u7c7b\u578b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Type generic = typeof(List&lt;&gt;);\nType concrete = generic.MakeGenericType(typeof(string));\nobject instance = Activator.CreateInstance(concrete);<\/code><\/pre>\n\n\n\n<p>\u9002\u5408<strong>\u901a\u7528\u6846\u67b6\u8bbe\u8ba1<\/strong>\u3001<strong>\u63d2\u4ef6\u7cfb\u7edf<\/strong>\u7b49\u9ad8\u7ea7\u573a\u666f\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">9\ufe0f\u20e3 \u6cdb\u578b\u7684\u5c40\u9650\u6027<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6cdb\u578b\u4e0d\u652f\u6301\u8fd0\u7b97\u7b26\u7ea6\u675f\uff08\u5982 <code>T + T<\/code>\uff09 \u2192 \u53ef\u901a\u8fc7\u59d4\u6258\u6216\u8868\u8fbe\u5f0f\u6811\u89e3\u51b3<\/li>\n\n\n\n<li>\u6cdb\u578b\u4e0d\u652f\u6301\u90e8\u5206\u7c7b\u578b\u63a8\u65ad\uff08\u590d\u6742\u7ea6\u675f\u65f6\uff09<\/li>\n\n\n\n<li>\u6cdb\u578b\u5b9e\u4f8b\u4e0d\u80fd\u76f4\u63a5\u4e3a <code>null<\/code>\uff08\u503c\u7c7b\u578b\uff09<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83d\udd1f \u5b9e\u6218\u8bbe\u8ba1\u6a21\u5f0f\u4e2d\u7684\u6cdb\u578b\u5e94\u7528<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u6a21\u5f0f<\/th><th>\u4f7f\u7528\u6cdb\u578b<\/th><th>\u793a\u4f8b<\/th><\/tr><\/thead><tbody><tr><td>\u4ed3\u50a8\u6a21\u5f0f\uff08Repository\uff09<\/td><td><code>IRepository&lt;T&gt;<\/code><\/td><td>\u7edf\u4e00\u6570\u636e\u8bbf\u95ee\u63a5\u53e3<\/td><\/tr><tr><td>\u5355\u4f8b\u6a21\u5f0f<\/td><td><code>Singleton&lt;T&gt;<\/code><\/td><td>\u6cdb\u578b\u5355\u4f8b\u7c7b<\/td><\/tr><tr><td>\u5de5\u5382\u6a21\u5f0f<\/td><td><code>Factory&lt;T&gt;<\/code><\/td><td>\u81ea\u52a8\u521b\u5efa\u6cdb\u578b\u5b9e\u4f8b<\/td><\/tr><tr><td>\u670d\u52a1\u5b9a\u4f4d\u5668<\/td><td><code>GetService&lt;T&gt;()<\/code><\/td><td>\u52a8\u6001\u89e3\u6790\u4f9d\u8d56<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Singleton&lt;T&gt; where T : new()\n{\n    private static T _instance = new T();\n    public static T Instance =&gt; _instance;\n}<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"> \u6cdb\u578b\u6700\u4f73\u5b9e\u8df5<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f7f\u7528 <code>where<\/code> \u9650\u5b9a\u7c7b\u578b\u529f\u80fd<\/li>\n\n\n\n<li>\u4e0d\u8981\u6ee5\u7528\u6cdb\u578b\uff0c\u903b\u8f91\u4e0d\u590d\u7528\u65f6\u4f18\u5148\u4f7f\u7528\u5177\u4f53\u7c7b\u578b<\/li>\n\n\n\n<li>\u7ed3\u5408 <code>Func&lt;><\/code> \u7b49\u6cdb\u578b\u59d4\u6258\u53ef\u5b9e\u73b0\u51fd\u6570\u5f0f\u7f16\u7a0b\u98ce\u683c<\/li>\n\n\n\n<li>\u7406\u89e3\u534f\u53d8\/\u9006\u53d8\u53ef\u63d0\u5347\u63a5\u53e3\u8bbe\u8ba1\u7075\u6d3b\u6027<\/li>\n\n\n\n<li>\u4f7f\u7528 <code>default(T)<\/code> \u83b7\u53d6\u9ed8\u8ba4\u503c\uff08int: 0, string: null\uff09<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u6df1\u5165\u5b66\u4e60\u8d44\u6e90\u63a8\u8350<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\ud83d\udcd8 \u5b98\u65b9\u6cdb\u578b\u624b\u518c\uff08\u8d85\u8be6\u7ec6\uff09<br>https:\/\/learn.microsoft.com\/en-us\/dotnet\/csharp\/programming-guide\/generics\/<\/li>\n\n\n\n<li>\ud83d\udcd8 \u6cdb\u578b\u96c6\u5408\u7ed3\u6784\u6e90\u7801\u53c2\u8003\uff08\u5982 List \u6e90\u7801\uff09<br>https:\/\/source.dot.net\/<\/li>\n\n\n\n<li>\ud83d\udcd8 \u9ad8\u7ea7\u6cdb\u578b\u8bbe\u8ba1\uff08\u534f\u53d8\/\u6cdb\u578b\u5de5\u5382\uff09<br>https:\/\/learn.microsoft.com\/en-us\/dotnet\/standard\/generics\/<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e0b\u9762\u662f\u4e00\u4e2a\u4ece\u4e13\u4e1a\u5f00\u53d1\u89d2\u5ea6\u51fa\u53d1\u3001\u5168\u9762\u6df1\u5165\u3001\u9644\u6743\u5a01\u94fe\u63a5\u7684\u3010C# \u6cdb\u578b\uff08Generic\uff09\u3011\u5b66\u4e60\u4e0e\u53c2\u8003\u6307\u5357\u3002 1\ufe0f\u20e3  [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":3592,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[83],"tags":[],"class_list":["post-3591","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-c-"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3591","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=3591"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3591\/revisions"}],"predecessor-version":[{"id":3593,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3591\/revisions\/3593"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media\/3592"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=3591"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=3591"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=3591"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}