可以使用哪些方法使线程等待事件，然后继续执行？ [英] Which methods can be used to make thread wait for an event and then continue its execution?

问题描述

我有一个线程运行，委托一些任务。当一个任务完成时，会发出一个事件已经完成了。这些任务需要以特定的顺序运行，需要等待上一个任务完成。如何让线程等待，直到收到任务完成事件？ （除了明显的事件处理者设置一个标志，然后一个循环轮询该标志）

解决方案

我经常使用 AutoResetEvent 等待句柄，当我需要等待异步任务完成：

  public void PerformAsyncTasks（）
 {
 SomeClass someObj = new SomeClass（）
 AutoResetEvent waitHandle = new AutoResetEvent（false）; 
 //为已完成事件创建并附加事件处理程序
 EventHandler eventHandler = delegate（object sender，EventArgs e）
 {
 waitHandle.Set（）; //表示完成的事件被提升
} 
 someObj.TaskCompleted + = eventHandler; 
 
 //调用异步方法
 someObj.PerformFirstTaskAsync（）; 
 //等到事件处理程序被调用
 waitHandle.WaitOne（）; 
 //已完成的事件已经被提出，继续下一个
 someObj.PerformSecondTaskAsync（）; 
 waitHandle.WaitOne（）; 
 // ...等等
} 
  

I have a thread running that delegates out some tasks. When a single task is complete, an event is raised saying that it has completed. These tasks need to be run in a specific order and need to wait for the previous task to finish. How can I make the thread wait until it receives the "task completed" event? (Aside from the obvious eventhandler that sets a flag and then a while loop polling the flag)

解决方案

I often use the AutoResetEvent wait handle when I need to wait for an asynchronous task to finish:

public void PerformAsyncTasks()
{
    SomeClass someObj = new SomeClass()
    AutoResetEvent waitHandle = new AutoResetEvent(false); 
    // create and attach event handler for the "Completed" event
    EventHandler eventHandler = delegate(object sender, EventArgs e) 
    {
        waitHandle.Set();  // signal that the finished event was raised
    } 
    someObj.TaskCompleted += eventHandler;

    // call the async method
    someObj.PerformFirstTaskAsync();    
    // Wait until the event handler is invoked
    waitHandle.WaitOne();
    // the completed event has been raised, go on with the next one
    someObj.PerformSecondTaskAsync();
    waitHandle.WaitOne();
    // ...and so on
}

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