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我可以等待一个特定的后台线程完成,然后另一个后台线程开始吗?[已关闭]
原标题:Can I wait for a specific background thread finish, then another background thread starts? [closed]
问题回答

在.NET4中,您可以使用Task而不是线程,然后使用continuations来实现您的目标:

var firstTask = Task.Factory.StartNew( () => PerformSomeLongRunningAction(); );

var secondTask = firstTask.ContinueWith( t => PerformSecondAction(); );

在.NET<=3.5,选项各不相同。最好的方法是经常使用WaitHandle来表示您的第二个任务。完成后,第一个后台线程需要向等待句柄发出信号:

var mre = new ManualResetEvent(false);

ThreadPool.QueueUserWorkItem( o =>
      {
           PerformSomeLongRunningAction();
           mre.Set(); // Signal to second thread that it can continue
      });

ThreadPool.QueueUserWorkItem( o =>
      {
           mre.WaitOne(); // Wait for first thread to finish
           PerformSecondAction();
      });

当然让第一个线程启动第二个线程,或者设置某种标志,告诉托管应用程序启动第二线程。当然,我不得不问:如果这些线程总是按顺序运行,为什么要创建第二个线程,而不是在第一个线程中执行所有工作?

如果您提供更多信息,我们可以在答案中提供更多细节。

通常,您可以设置一个通信系统(消息队列、事件或委托),用于发出进程/步骤/线程已完成的信号。当这种情况发生时,启动下一个线程。





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