{"id":1226,"date":"2022-05-15T16:47:06","date_gmt":"2022-05-15T08:47:06","guid":{"rendered":"https:\/\/summid.icu\/?p=1226"},"modified":"2022-06-20T22:38:19","modified_gmt":"2022-06-20T14:38:19","slug":"extending-the-async-methods-in-c","status":"publish","type":"post","link":"https:\/\/summid.icu\/index.php\/2022\/05\/15\/extending-the-async-methods-in-c\/","title":{"rendered":"\u62d3\u5c55C#\u7684\u5f02\u6b65\u65b9\u6cd5"},"content":{"rendered":"

\u672c\u6587\u624b\u52a8\u7ffb\u8bd1\u81ea\uff1aExtending the async methods in C#<\/a><\/p>\n

\u4e0a\u4e00\u7bc7\u6587\u7ae0\u4e2d\uff0c\u6211\u4eec\u8ba8\u8bba\u4e86 C# \u7f16\u8bd1\u5668\u662f\u5982\u4f55\u5904\u7406\u5f02\u6b65\u65b9\u6cd5\u7684\u3002\u5728\u8fd9\u4e00\u7bc7\uff0c\u6211\u4eec\u4f1a\u91cd\u70b9\u5173\u6ce8 C# \u7f16\u8bd1\u5668\u4e3a\u81ea\u5b9a\u4e49\u5f02\u6b65\u65b9\u6cd5\u63d0\u4f9b\u7684\u53ef\u6269\u5c55\u6027\u3002<\/span><\/p>\n

\u6211\u4eec\u6709\u4e09\u79cd\u63a7\u5236\u5f02\u6b65\u65b9\u6cd5\u72b6\u6001\u673a\u7684\u601d\u8def\uff1a<\/span><\/p>\n

    \n
  1. \n

    \u5728 <\/span>System.Runtime.CompilerServices<\/code><\/span> \u547d\u540d\u7a7a\u95f4\u4e2d\u63d0\u4f9b\u81ea\u5df1\u7684\u5f02\u6b65\u65b9\u6cd5 <\/span>builder<\/code><\/span> \u3002<\/span><\/p>\n<\/li>\n

  2. \n

    \u81ea\u5b9a\u4e49 <\/span>task awaiters<\/code><\/span> \u3002<\/span><\/p>\n<\/li>\n

  3. \n

    \u81ea\u5b9a\u4e49 <\/span>task-like<\/code><\/span> \u7c7b\u3002<\/span><\/p>\n<\/li>\n<\/ol>\n

    \u5728 <\/span>System.Runtime.ComplierServices<\/code><\/span> \u547d\u540d\u7a7a\u95f4\u4e0b\u81ea\u5b9a\u4e49 <\/span>AsyncMethodBuilder<\/code><\/span> \u7c7b<\/span><\/h2>\n

    \u4ece\u524d\u6587\u6211\u4eec\u5f97\u77e5\uff0cC# \u7f16\u8bd1\u5668\u4f1a\u4f9d\u636e\u4e00\u4e9b\u7cfb\u7edf\u63d0\u4f9b\u7684\u7c7b\u5c06\u5f02\u6b65\u65b9\u6cd5\u8f6c\u6362\u4e3a\u72b6\u6001\u673a\u3002\u4f46 C# \u7f16\u8bd1\u5668\u5e76\u4e0d\u8981\u6c42\u6240\u4f9d\u636e\u7684\u7c7b\u6765\u81ea\u6307\u5b9a\u7684\u67d0\u4e2a\u7a0b\u5e8f\u96c6\u3002\u4f8b\u5982\uff0c\u6211\u4eec\u53ef\u4ee5\u5728\u9879\u76ee\u4e2d\u63d0\u4f9b\u81ea\u5df1\u7684 <\/span>AsyncVoidMethodBuilder<\/code><\/span><\/a><\/span> \uff0c\u8fd9\u6837 C# \u7f16\u8bd1\u5668\u4f1a\u5c06\u5f02\u6b65\u673a\u5236\u4e0e\u8be5\u7c7b\u201c\u7ed1\u5b9a\u201d\u3002<\/span><\/p>\n

    \u4e0b\u9762\u7684\u4f8b\u5b50\u5c06\u5e2e\u52a9\u6211\u4eec\u7406\u89e3\u5e95\u5c42\u8f6c\u6362\uff0c\u5e76\u770b\u770b\u4ee3\u7801\u8fd0\u884c\u65f6\u53d1\u751f\u7684\u4e8b\u60c5\uff1a<\/span><\/p>\n\n\n

    namespace System.Runtime.CompilerServices\r\n{\r\n    \/\/ AsyncVoidMethodBuilder.cs in your project\r\n    public class AsyncVoidMethodBuilder\r\n    {\r\n        public AsyncVoidMethodBuilder()\r\n            => Console.WriteLine(\".ctor\");\r\n \r\n        public static AsyncVoidMethodBuilder Create()\r\n            => new AsyncVoidMethodBuilder();\r\n \r\n        public void SetResult() => Console.WriteLine(\"SetResult\");\r\n \r\n        public void Start<TStateMachine>(ref TStateMachine stateMachine)\r\n            where TStateMachine : IAsyncStateMachine\r\n        {\r\n            Console.WriteLine(\"Start\");\r\n            stateMachine.MoveNext();\r\n        }\r\n \r\n        \/\/ AwaitOnCompleted, AwaitUnsafeOnCompleted, SetException \r\n        \/\/ and SetStateMachine are empty\r\n    }   \r\n}<\/code><\/pre>\n\n\n
    \u73b0\u5728\uff0c\u9879\u76ee\u4e2d\u7684\u6bcf\u4e2a\u5f02\u6b65\u65b9\u6cd5\u4f1a\u91c7\u7528\u81ea\u5b9a\u4e49\u7248\u672c\u7684 <\/span>AsyncVoidMethodBuilder<\/code><\/span> \u3002\u6211\u4eec\u53ef\u4ee5\u7b80\u5355\u6d4b\u8bd5\u4e00\u4e0b\uff1a<\/span><\/p>\n\n\n
    [Test]\r\npublic void RunAsyncVoid()\r\n{\r\n    Console.WriteLine(\"Before VoidAsync\");\r\n    VoidAsync();\r\n    Console.WriteLine(\"After VoidAsync\");\r\n \r\n    async void VoidAsync() { }\r\n}<\/code><\/pre>\n\n\n
    \u8be5\u6d4b\u8bd5\u7684\u8f93\u51fa\uff1a<\/p>\n\n\n
    Before VoidAsync\r\n.ctor\r\nStart\r\nSetResult\r\nAfter VoidAsync<\/code><\/pre>\n\n\n
    \u4f60\u8fd8\u53ef\u4ee5\u5b9e\u73b0 <\/span>UnsafeAwaitOnComplete<\/code><\/span> \u65b9\u6cd5\uff0c\u6765\u8bd5\u9a8c\u5f53\u5f02\u6b65\u65b9\u6cd5\u8fd4\u56de\u8fd8\u6ca1\u5b8c\u6210\u4efb\u52a1\u7684 <\/span>Task<\/code><\/span> \u5bf9\u8c61\u7684\u65f6\u5019\u7684\u60c5\u51b5\u3002\u5b8c\u6574\u7684\u4f8b\u5b50\u53ef\u4ee5\u5728 <\/span>github<\/span><\/a><\/span> \u627e\u5230\u3002<\/span><\/p>\n
    \u8981\u4fee\u6539 <\/span>async Task<\/code><\/span> \u548c <\/span>async Task<T><\/code><\/span> \u65b9\u6cd5\u7684\u884c\u4e3a\uff0c\u4f60\u9700\u8981\u63d0\u4f9b\u81ea\u5b9a\u4e49\u7248\u672c\u7684 <\/span>AsyncTaskMethodBuilder<\/code><\/span><\/a><\/span> \u548c <\/span>AsyncTaskMethodBuilder<\/code><\/span><\/a><\/span> \u3002<\/span><\/p>\n
    \u5173\u4e8e\u4e0a\u9762\u63d0\u5230\u7684\u7c7b\uff0c\u53ef\u4ee5\u5728 github \u4e0a\u7684 <\/span>EduAsync<\/span><\/a><\/span> \u9879\u76ee\u91cc\u627e\u5230\u53c2\u8003\uff1a <\/span>AsyncTaskBuilder.cs<\/span><\/a><\/span> \u548c <\/span>AsyncTaskMethodBuilderOfT.cs<\/span><\/a><\/span> \u3002<\/span><\/p>\n
    \u611f\u8c22 <\/span>Jon Skeet<\/span><\/a><\/span> \u5728\u8fd9\u9879\u76ee\u4e0a\u7ed9\u4e88\u6211\uff08\u4f5c\u8005\uff09\u7684\u7075\u611f\u3002<\/span><\/p>\n
    \u81ea\u5b9a\u4e49 awaiters<\/span><\/h2>\n
    \u524d\u9762\u7684\u4f8b\u5b50\u6709\u4ebf\u70b9 “\u9ed1\u9b54\u6cd5” \u7684\u5473\u9053\uff0c\u5e76\u4e14\u5b83\u4e0d\u9002\u5408\u7528\u5728\u771f\u6b63\u7684\u751f\u4ea7\u73af\u5883\u91cc\u3002\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5b83\u5b66\u4e60\u5f02\u6b65\u673a\u5236\uff0c\u4f46\u4f60\u80af\u5b9a\u4e0d\u60f3\u770b\u5230\u8fd9\u4e9b\u4ee3\u7801\u51fa\u73b0\u5728\u81ea\u5df1\u7684\u9879\u76ee\u91cc\u3002\u597d\u5728 C# \u4f5c\u8005\u7ed9\u7f16\u8bd1\u5668\u5185\u7f6e\u4e86\u53ef\u6269\u5c55\u7684\u70b9\uff0c\u5141\u8bb8\u5728\u5f02\u6b65\u65b9\u6cd5\u4e2d <\/span>await<\/code><\/span> \u4e0d\u540c\u7684\u5bf9\u8c61\u7c7b\u578b\u3002<\/span><\/p>\n
    \u53ef\u88ab <\/span>await<\/code><\/span> \u7684\u7c7b\uff08\u5373\u5728 <\/span>await<\/code><\/span> \u8868\u8fbe\u5f0f\u4e2d\u5408\u6cd5\uff09\u9700\u8981\u6ee1\u8db3\u4ee5\u4e0b\u51e0\u4e2a\u6761\u4ef6\uff1a<\/span><\/p>\n