一般來說線程都是有自己上下文，變量是不共享的，這就需要線程本地存儲
public static class TlsSample { [ThreadStatic] public static int a; [ThreadStatic] public static int b; public static void Thread1() { a = 1; b = 2; Console.WriteLine($"a={a} [From Thread1]"); Console.WriteLine($"b={b} [From Thread1]"); } public static void Thread2() { a = 10; b = 20; Console.WriteLine($"a={a} [From Thread2]"); Console.WriteLine($"b={b} [From Thread2]"); } public static void Run() { var thread1 = new Thread(Thread1); var thread2 = new Thread(Thread2); thread1.Start(); thread2.Start(); } }
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public class ThreadLocalSample { public readonly ThreadLocal a = new ThreadLocal(); public readonly ThreadLocal b = new ThreadLocal(); public void Thread1() { a.Value = 1; b.Value = 2; Console.WriteLine($"a={a} [From Thread1]"); Console.WriteLine($"b={b} [From Thread1]"); } public void Thread2() { a.Value = 10; b.Value = 20; Console.WriteLine($"a={a} [From Thread2]"); Console.WriteLine($"b={b} [From Thread2]"); } public void Run() { var thread1 = new Thread(Thread1); var thread2 = new Thread(Thread2); thread1.Start(); thread2.Start(); } }
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異步本地變量AsyncLocal（執行上下文）
public static class Sample07 { private static readonly ThreadLocal ThreadLocal = new ThreadLocal(); private static readonly AsyncLocal AsyncLocal = new AsyncLocal(); public static async Task Run() { ThreadLocal.Value = 10; AsyncLocal.Value = 10; Console.WriteLine($"Tid={Thread.CurrentThread.ManagedThreadId};" + $"ThreadLocal={ThreadLocal.Value};" + $"AsyncLocal={AsyncLocal.Value}"); await Task.Delay(1000); Console.WriteLine($"Tid={Thread.CurrentThread.ManagedThreadId};" + $"ThreadLocal={ThreadLocal.Value};" + $"AsyncLocal={AsyncLocal.Value}"); } }
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不變性值類型子任務異步變量修改不會變，引用會
public static class Sample08 { private static readonly AsyncLocal AsyncLocal = new AsyncLocal(); public static async Task ParentTask() { AsyncLocal.Value = 111; Console.WriteLine($"ParentTask Begin:AsyncLocal={AsyncLocal.Value}"); await ChildTask(); Console.WriteLine($"ParentTask End:AsyncLocal={AsyncLocal.Value}"); } public static async Task ChildTask() { Console.WriteLine($"ChildTask Begin:AsyncLocal={AsyncLocal.Value}"); AsyncLocal.Value = 222; await Task.Delay(1000); Console.WriteLine($"ChildTask End:AsyncLocal={AsyncLocal.Value}"); } }
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禁止捕捉執行上下文，則無法傳遞到其他線程
public static class Sample11 { private static readonly AsyncLocal AsyncLocal = new AsyncLocal(); public static async Task ParentTask() { AsyncLocal.Value = 111; Console.WriteLine($"ParentTask Begin:AsyncLocal={AsyncLocal.Value}"); // 禁止捕捉執行上下文 var control = ExecutionContext.SuppressFlow(); Task.Delay(100).ContinueWith(task => { Console.WriteLine($"SuppressFlow:AsyncLocal={AsyncLocal.Value}"); }); // 恢復捕捉上下文 control.Undo(); // 捕捉到的執行上下文為null await Task.Delay(100); Console.WriteLine($"Undo:AsyncLocal={AsyncLocal.Value}"); } }
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.NET 任務調度
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版權聲明：本文內容由網絡用戶投稿，版權歸原作者所有，本站不擁有其著作權，亦不承擔相應法律責任。如果您發現本站中有涉嫌抄襲或描述失實的內容，請聯系我們jiasou666@gmail.com 處理，核實后本網站將在24小時內刪除侵權內容。
