WPF中的BackgroundWorker.RunWorkerCompleted事件 [英] BackgroundWorker.RunWorkerCompleted event in WPF

问题描述

在某些情况下，用户仍在通过BackgroundWorker处理数据时终止了该应用程序.我想向该方法发送取消或终止命令.我尝试调用CancelAsync()方法，但是它显然没有按我预期的方式工作，并且工作程序仍在继续处理.用什么好方法来通知BackgroundWorker，尤其是其RunWorkerCompleted方法停止处理?我必须使用状态变量吗?

There is a scenario in which a user terminates the application, while it is still processing data via BackgroundWorker. I would like to send cancel or terminate command to this method. I tried calling CancelAsync() method, but it obviously didn't work the way I expected and the worker still continued processing. What is a good way to signal the BackgroundWorker, and especially its RunWorkerCompleted method to stop processing? Do I have to use state variables?

推荐答案

这是在BackgroundWorker上调用CancelAsync()时执行的代码

This is the code executed when you call CancelAsync() on a BackgroundWorker

public void CancelAsync()
{
    if (!this.WorkerSupportsCancellation)
    {
        throw new InvalidOperationException(SR.GetString
                 ("BackgroundWorker_WorkerDoesntSupportCancellation"));
    }
    this.cancellationPending = true;
}

如您所见，他们在检查了 WorkerSupportsCancellation 的值之后，将内部 cancellationPending 变量设置为true.

As you can see, they set the internal cancellationPending variable to true after checking the value of WorkerSupportsCancellation.

因此，当您退出应用程序调用 backGroundWorkerInstance.CancelAsync()并在DoWork或RunWorkerCompleted内部测试时，您需要设置 WorkerSupportsCancellation = true; .如果是这样，请停止您的过程.

So you need to set WorkerSupportsCancellation = true;, when you exit from your app call backGroundWorkerInstance.CancelAsync() and inside the DoWork or RunWorkerCompleted test the CancellationPending. If it's true stop your process.

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