{"id":1239,"date":"2022-07-17T11:59:08","date_gmt":"2022-07-17T03:59:08","guid":{"rendered":"https:\/\/summid.icu\/?p=1239"},"modified":"2022-10-13T20:20:08","modified_gmt":"2022-10-13T12:20:08","slug":"one-user-scenario-to-rule-them-all","status":"publish","type":"post","link":"https:\/\/summid.icu\/index.php\/2022\/07\/17\/one-user-scenario-to-rule-them-all\/","title":{"rendered":"\u7528\u4e00\u4e2a\u7528\u4f8b\u66f4\u6df1\u5165\u4e86\u89e3C#\u5f02\u6b65\u65b9\u6cd5"},"content":{"rendered":"

\u672c\u6587\u624b\u52a8\u7ffb\u8bd1\u81ea\uff1aOne user scenario to rule them all – Developer Support (microsoft.com)<\/a><\/p>\n

\u51e0\u4e4e\u6240\u6709C#\u5f02\u6b65\u65b9\u6cd5\u7684\u7279\u6b8a\u884c\u4e3a\u90fd\u53ef\u4ee5\u7528\u4e00\u4e2a\u7528\u4f8b\u89e3\u91ca\uff1a\u5c06\u73b0\u6709\u7684\u540c\u6b65\u4ee3\u7801\u4fee\u6539\u4e3a\u5f02\u6b65\u4ee3\u7801\u5e94\u8be5\u5c3d\u53ef\u80fd\u7b80\u5355\u3002\u4f60\u5e94\u8be5\u80fd\u591f\u5728\u65b9\u6cd5\u7684\u8fd4\u56de\u7c7b\u578b\u524d\u9762\u6dfb\u52a0 <\/span>async<\/code><\/span> \u5173\u952e\u5b57\uff0c\u518d\u5728\u65b9\u6cd5\u540d\u540e\u6dfb\u52a0 <\/span>Async<\/code><\/span> \u540e\u7f00\uff0c\u6700\u540e\u5728\u65b9\u6cd5\u4e2d\u5404\u5904\u4f7f\u7528 <\/span>await<\/code><\/span> \u5173\u952e\u5b57\uff0c\u6765\u5f97\u5230\u62e5\u6709\u5b8c\u6574\u529f\u80fd\u7684\u5f02\u6b65\u65b9\u6cd5\uff1a<\/span><\/p>\n\n\n

\/\/\u540c\u6b65\u4ee3\u7801\nprivate void buttonOk_Click(object sender, EventArgs args)\n{\n    textBox.Text = \"Running..\";\n    var result = _stockPrices.GetStockPricesFor(\"MSFT\");\n    textBox.Text = \"Result is:\" + result;\n}\n\/\/\u5c06\u540c\u6b65\u4ee3\u7801\u8f6c\u6362\u4e3a\u5f02\u6b65\u4ee3\u7801\n\/\/\u5f02\u6b65\u4ee3\u7801\nprivate async void buttonOk_ClickAsync(object sender, EventArgs args)\n{\n    textBox.Text = \"Running..\";\n    var result = await _stockPrices.GetStockPricesFor(\"MSFT\");\n    textBox.Text = \"Result is:\" + result;\n}<\/code><\/pre>\n\n\n
\u8fd9\u4e2a\u3010\u7b80\u5355\u7684\u3011\u7528\u4f8b\uff08\u540c\u6b65\u4ee3\u7801\u8f6c\u6362\u4e3a\u5f02\u6b65\u65b9\u6cd5\uff09\u6539\u53d8\u4e86\u5f02\u6b65\u65b9\u6cd5\u884c\u4e3a\u7684\u8bb8\u591a\u65b9\u9762\uff1a\u4f8b\u5982\u7eed\u4f53\u4efb\u52a1\u7684\u8c03\u5ea6\u548c\u5f02\u5e38\u5904\u7406\u3002\u8be5\u7528\u4f8b\u770b\u4e0a\u53bb\u5f88\u7b80\u5355\uff0c\u4f46\u5b83\u4f1a\u8ba9\u8fd9\u79cd\u7b80\u5355\u6027\u975e\u5e38\u5177\u6709\u6b3a\u9a97\u6027\u3002<\/span><\/p>\n
\u540e\u6587\u4f1a\u518d\u6b21\u63d0\u5230\u8be5\u7528\u4f8b\u3002<\/span><\/p>\n
\u540c\u6b65\u4e0a\u4e0b\u6587<\/span><\/h2>\n
UI\u5f00\u53d1\u662f\u4e0a\u8ff0\u573a\u666f\u975e\u5e38\u91cd\u8981\u7684\u9886\u57df\u4e4b\u4e00\u3002UI\u7ebf\u7a0b\u4e2d\u957f\u65f6\u95f4\u8fd0\u884c\u7684\u64cd\u4f5c\u4f1a\u5bfc\u81f4\u7a0b\u5e8f\u65e0\u54cd\u5e94\uff0c\u56e0\u6b64\u5f02\u6b65\u7f16\u7a0b\u4e00\u76f4\u88ab\u8ba4\u4e3a\u662f\u4e00\u4e2a\u5f88\u597d\u7684\u9009\u62e9\u3002<\/span><\/p>\n\n\n
private async void buttonOk_ClickAsync(object sender, EventArgs args)\n{\n    textBox.Text = \"Running..\"; \/\/ 1 -- UI Thread\n    var result = await _stockPrices.GetStockPricesForAsync(\"MSFT\"); \/\/ 2 -- Usually non-UI Thread\n    textBox.Text = \"Result is: \" + result; \/\/3 -- Should be UI Thread\n}<\/code><\/pre>\n\n\n
\u4e0a\u9762\u7684\u4ee3\u7801\u770b\u8d77\u6765\u5341\u5206\u7b80\u5355\uff0c\u4f46\u4ecd\u7136\u6709\u4e00\u4e2a\u95ee\u9898\uff1a\u8bb8\u591aUI\u6846\u67b6\u53ea\u5141\u8bb8\u7279\u5b9a\u7684\u7ebf\u7a0b\u64cd\u4f5cUI\u5143\u7d20\u3002\u8fd9\u610f\u5473\u7740\u5982\u679c\u7b2c\u4e09\u884c\u4ee3\u7801\u88ab\u8c03\u5ea6\u5230\u7ebf\u7a0b\u6c60\u4e2d\u7684\u7ebf\u7a0b\u65f6\u4f1a\u4ea7\u751f\u9519\u8bef\u3002\u5e78\u8fd0\u7684\u662f\uff0c\u8fd9\u4e2a\u95ee\u9898\u6bd4\u8f83\u4e45\u8fdc\u4e86\uff0c\u5728 <\/span>.NET Framework2.0<\/code><\/span> \u95ee\u4e16\u65f6\uff0c\u3010<\/span>\u540c\u6b65\u4e0a\u4e0b\u6587<\/span><\/a><\/span>\u3011\uff08Synchronization Contexts\uff09\u6982\u5ff5\u4e5f\u968f\u4e4b\u5230\u6765\u3002<\/span><\/p>\n
\u6bcf\u4e2aUI\u6846\u67b6\u90fd\u4f1a\u63d0\u4f9b\u7528\u4e8e\u5c06\u5de5\u4f5c\u7f16\u7ec4\u5230\u4e13\u7528UI\u7ebf\u7a0b\uff08\u53ef\u80fd\u6709\u591a\u4e2aUI\u7ebf\u7a0b\uff09\u4e2d\u7684\u516c\u5171\u63a5\u53e3\u3002<\/span>Windows Forms<\/code><\/span> \u6709 <\/span>Control.Invoke<\/span><\/a><\/span> \uff0c<\/span>WPF<\/code><\/span> \u5219\u6709 <\/span>Dispatcher.Invoke<\/span><\/a><\/span>\uff0c\u5176\u4ed6\u6846\u67b6\u5927\u6982\u7387\u4e5f\u4f1a\u6709\u81ea\u5df1\u7684\u63a5\u53e3\u3002\u6240\u6709\u4f8b\u5b50\u7684\u539f\u7406\u90fd\u662f\u76f8\u4f3c\u7684\uff0c\u4f46\u5b9e\u73b0\u7ec6\u8282\u5374\u6709\u6240\u4e0d\u540c\u3002\u540c\u6b65\u4e0a\u4e0b\u6587\u4f5c\u4e3a\u57fa\u7c7b\uff0c\u5c06\u5dee\u5f02\u62bd\u8c61\u51fa\u6765\uff0c\u5e76\u63d0\u4f9b\u4e00\u4e2aAPI\u7528\u4e8e\u5728\u67d0\u4e2a\u4e0a\u4e0b\u6587\u4e2d\u8fd0\u884c\u4ee3\u7801\uff0c\u6700\u540e\u628a\u7ec6\u8282\u7559\u7ed9\u6d3e\u751f\u7c7b\uff0c\u6bd4\u5982 <\/span>WindowsFormsSynchronizationContext<\/span><\/a><\/span>\uff0c<\/span>DispatcherSynchronizatioinContext<\/span><\/a><\/span> \u7b49\u7b49\u3002<\/span><\/p>\n
\u4e3a\u4e86\u89e3\u51b3\u7ebf\u7a0b\u5173\u8054\u95ee\u9898\uff0cC#\u4f5c\u8005\u51b3\u5b9a\u5728\u5f02\u6b65\u65b9\u6cd5\u5f00\u59cb\u6267\u884c\u65f6\u6355\u83b7\u5f53\u524d\u7684\u540c\u6b65\u4e0a\u4e0b\u6587\uff0c\u7136\u540e\u628a\u6240\u6709\u7684\u7eed\u4f53\u90fd\u8c03\u5ea6\u5230\u8be5\u4e0a\u4e0b\u6587\u91cc\u3002\u6b63\u56e0\u5982\u6b64\uff0c\u6bcf\u4e2a <\/span>await<\/code><\/span> \u8bed\u53e5\u4e4b\u95f4\u7684\u4ee3\u7801\u90fd\u4f1a\u5728UI\u7ebf\u7a0b\u91cc\u6267\u884c\uff0c\u8fd9\u5c31\u8ba9\u6211\u4eec\u7684\u7528\u4f8b\u80fd\u591f\u8dd1\u8d77\u6765\u3002\u4f46\u8be5\u89e3\u51b3\u65b9\u6848\u8fd8\u662f\u5e26\u6765\u4e86\u4e00\u5927\u5806\u7684\u5176\u4ed6\u6311\u6218\u3002<\/span><\/p>\n
\u6b7b\u9501<\/span><\/h2>\n
\u5148\u6765\u770b\u770b\u548c\u7528\u4f8b\u7c7b\u4f3c\u7684\u4ee3\u7801\u7247\u6bb5\u3002\u80fd\u53d1\u73b0\u6709\u4f55\u95ee\u9898\u561b\uff1f<\/span><\/p>\n\n\n
\/\/ UI code\nprivate void buttonOk_Click(object sender, EventArgs args)\n{\n    textBox.Text = \"Running..\";\n    var result = _stockPrices.GetStockPricesForAsync(\"MSFT\").Result;\n    textBox.Text = \"Result is: \" + result;\n}\n \n\/\/ StockPrices.dll\npublic Task<decimal> GetStockPricesForAsync(string symbol)\n{\n    await Task.Yield();\/\/line 1\n    return 42;\/\/line 2\n}<\/code><\/pre>\n\n\n
\u8be5\u4ee3\u7801\u4f1a\u5bfc\u81f4\u4e00\u9879\u6b7b\u9501<\/span><\/strong><\/span>\u3002UI\u7ebf\u7a0b\u542f\u52a8\u5f02\u6b65\u64cd\u4f5c\u7136\u540e\u540c\u6b65\u7b49\u5f85\u7ed3\u679c\u3002\u4f46\u56e0\u4e3a <\/span>GetStockPricesForAsync<\/code><\/span> \u7684\u7b2c\u4e8c\u884c\u5e94\u8be5\u5728UI\u7ebf\u7a0b\u4e2d\u8fd0\u884c\uff0c\u6240\u4ee5\u5bfc\u81f4\u4e86\u8be5\u5f02\u6b65\u65b9\u6cd5\u65e0\u6cd5\u5b8c\u6210\u7684\u6b7b\u9501\u3002<\/span><\/p>\n
\u4f60\u53ef\u80fd\u4f1a\u8bf4\uff0c\u8fd9\u4e2a\u95ee\u9898\u662f\u6bd4\u8f83\u5bb9\u6613\u53d1\u73b0\u7684\uff0c\u5e76\u4e14\u6211\u4e5f\u540c\u610f\u4f60\u7684\u89c2\u70b9\u3002UI\u4ee3\u7801\u5e94\u8be5\u7981\u6b62\u5bf9 <\/span>Task.Result<\/code><\/span> \u6216 <\/span>Task.Wait<\/code><\/span> \u7684\u4efb\u4f55\u8c03\u7528\uff0c\u4f46\u5982\u679cUI\u4ee3\u7801\u6240\u4f9d\u8d56\u7684\u7ec4\u4ef6\u6709\u540c\u6b65\u7b49\u5f85\u5f02\u6b65\u64cd\u4f5c\u7ed3\u679c\u7684\u60c5\u51b5\uff0c\u8be5\u95ee\u9898\u8fd8\u4f1a\u53d1\u751f\uff1a<\/span><\/p>\n\n\n
\/\/ UI code\nprivate void buttonOk_Click(object sender, EventArgs args)\n{\n    textBox.Text = \"Running..\";\n    var result = _stockPrices.GetStockPricesForAsync(\"MSFT\").Result;\n    textBox.Text = \"Result is: \" + result;\n}\n \n\/\/ StockPrices.dll\npublic Task<decimal> GetStockPricesForAsync(string symbol)\n{\n    \/\/ We know that the initialization step is very fast,\n    \/\/ and completes synchronously in most cases,\n    \/\/ let's wait for the result synchronously for \"performance reasons\".\n    InitializeIfNeededAsync().Wait();\n    return Task.FromResult((decimal)42);\n}\n \n\/\/ StockPrices.dll\nprivate async Task InitializeIfNeededAsync() => await Task.Delay(1);<\/code><\/pre>\n\n\n
\u4ee3\u7801\u8fd8\u662f\u4f1a\u6b7b\u9501\u3002\u73b0\u5728\uff0cC#\u5f02\u6b65\u7f16\u7a0b\u7684\u4e24\u4e2a\u3010\u4f17\u6240\u5468\u77e5\u3011\u7684\u6700\u4f73\u5b9e\u8df5\u6765\u5570\uff1a<\/span><\/p>\n