我如何正确地取消并重新启动一个BackgroundWorker的进程？ [英] How do I properly cancel and restart a BackgroundWorker process?

问题描述

用户到一个TextBox控件。

Users of my application type HTML into a TextBox control.

我想我的应用程序，以验证他们的投入在后台。

I want my application to validate their input in the background.

由于我不想锤验证服务，我试图建立在每个校验前一秒钟的延迟。

Because I don't want to hammer the validation service, I've tried to build in a one-second delay before each validation.

不过，我似乎并没有能够正确地中断一个已经运行的BackgroundWorker的过程。

However, I don't seem to be able to correctly interrupt an already-running BackgroundWorker process.

我的Visual Basic code：

My Visual Basic code:

Sub W3CValidate(ByVal WholeDocumentText As String)

    'stop any already-running validation
    If ValidationWorker.IsBusy Then
        ValidationWorker.CancelAsync()
        'wait for it to become ready
        While ValidationWorker.IsBusy
            'pause for one-hundredth of a second
            System.Threading.Thread.Sleep(New TimeSpan(0, 0, 0, 0, 10))
        End While
    End If

    'start validation
    Dim ValidationArgument As W3CValidator = New W3CValidator(WholeDocumentText)
    ValidationWorker.RunWorkerAsync(ValidationArgument)

End Sub

看来，叫我的BackgroundWorker的CancelAsync（）后，其IsBusy永远不会成为假。它被卡在一个无限循环。

It seems that after calling my BackgroundWorker's CancelAsync(), its IsBusy never becomes False. It gets stuck in an infinite loop.

我是什么做错了吗？

推荐答案

尝试是这样的：

bool restartWorker = false;

	void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
	{
                    // add other code here
		if (e.Cancelled && restartWorker)
		{
			restartWorker = false;
			backgroundWorker1.RunWorkerAsync();
		}
	}

	private void button1_Click(object sender, EventArgs e)
	{
		if (backgroundWorker1.IsBusy)
		{
			restartWorker = true;
			backgroundWorker1.CancelAsync();
		}
		else
			backgroundWorker1.RunWorkerAsync();
	}

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