取消后台任务 [英] Cancelling Background Tasks

问题描述

当我的C#应用​​程序关闭时，有时会陷入清理例程中.具体来说，后台工作人员没有关闭.基本上，这就是我试图关闭它的方式:

When my C# application closes it sometimes gets caught in the cleanup routine. Specifically, a background worker is not closing. This is basically how I am attempting to close it:

<罢工> 私有无效App_FormClosing(对象发送者，FormClosingEventArgs e) { backgroundWorker1.CancelAsync(); 而(backgroundWorker1.IsBusy);//卡在这里. }

private void App_FormClosing(object sender, FormClosingEventArgs e) { backgroundWorker1.CancelAsync(); while (backgroundWorker1.IsBusy) ; // Gets stuck here. }

我应该以其他方式执行此操作吗?我正在使用Microsoft Visual C#2008 Express Edition.谢谢.

Is there a different way that I should be doing this? I am using Microsoft Visual C# 2008 Express Edition. Thanks.

其他信息:

后台工作程序似乎没有退出.这就是我所拥有的:

The background worker does not appear to be exiting. This is what I have:

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
   while (!backgroundWorker1.CancellationPending)
   {
      // Do something.
   }
}

我还修改了清理代码:

private void App_FormClosing(object sender, FormClosingEventArgs e)
{
   while (backgroundWorker1.IsBusy)
   {
      backgroundWorker1.CancelAsync();
      System.Threading.Thread.Sleep(1000);
   }
}

还有什么我应该做的吗?

Is there something else that I should be doing?

推荐答案

Kevin大风正确地说明了您的BackgroundWorker的DoWork处理程序需要轮询CancellationPending并在请求取消的情况下返回.

Kevin Gale is correct in stating that your BackgroundWorker's DoWork handler needs to poll for CancellationPending and return if a cancellation is requested.

也就是说，如果在关闭应用程序时发生这种情况，您也可以安全地忽略它. BackgroundWorker使用ThreadPool线程，根据定义，该线程是后台线程.保持运行状态不会阻止您的应用程序终止，并且在您的应用程序关闭时线程将自动被关闭.

That being said, if this is happening when your application is shutting down, you can just ignore it safely, as well. BackgroundWorker uses a ThreadPool thread, which is, by definition, a background thread. Leaving this running will not prevent your application from terminating, and the thread will automatically be torn down when your application shuts down.

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