等待 BackgroundWorker 完成，如果 运行，在 FormClosing 时间

Question

如何等待 BackgroundWorker to finish, if running, when the user request to close application? I'd like to wait to this BackgroundWorker finish then exit application. I tried with AutoResetEvent but a call to WaitOne() at FormClosing time seems to block the entire UI and doesn't fire RunWorkerCompleted event where Set() 被调用。 我怎样才能做到这一点？

我正在为此寻找 alternative/proper 方法：

bool done = false;
        private void my_backgroundWorker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
        {
            resetEvent.Set();
            done = true;
        }

        private void myForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (notify_backgroundWorker.IsBusy)
            {
                while(!done)
                {
                    Application.DoEvents();
                    Thread.Sleep(500);
                }
                //resetEvent.WaitOne();
            }
        }

Answer 1

不用弄那么复杂，有一个class级变量就可以了

bool quitRequestedWhileWorkerBusy=false;

如果用户试图关闭表单，在表单关闭事件中检查工作人员是否忙碌，取消事件并设置quitRequestedWhileWorkerBusy=true

在您的工作人员完成事件中，if(quitRequestedWhileWorkerBusy) this.Close();

Answer 2

另一种方法是基于 OP 的示例代码，但经过简化：

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
    // Stop the background worker thread (if running) to avoid race hazard.
    if (backgroundWorker1.IsBusy)
    {
        backgroundWorker1.CancelAsync();

        // Wait for the background worker thread to actually finish.
        while (backgroundWorker1.IsBusy)
        {
            Application.DoEvents();
            Thread.Sleep(100);
        }
    }
}