How to wait two BackgrandWorker's RunWorkerCompleted event finished?

Question

That's the code:

   private void button1_Click(object sender, EventArgs e)
   {
        ParaClass pcs = new ParaClass();
        pcs.strPath = textBox1.Text;
        pcs.sendedGrid = ugSrc;
        this.backgroundWorker1.RunWorkerAsync(pcs);

        ParaClass pcsB = new ParaClass();
        pcsB.strPath = textBox2.Text;
        pcsB.sendedGrid = ultraGrid2;

        this.backgroundWorker2.RunWorkerAsync(pcsB);

        doSomething();
    }

and in both backgrandworker1 & backgrandworker2 ' complet event ,i write code like this:

    private void backgroundWorker1_RunWorkerCompleted(object sender,RunWorkerCompletedEventArgs e)
    {
           doSomethingelsebk1();
    }

    private void backgroundWorker2_RunWorkerCompleted(object sender,RunWorkerCompletedEventArgs e)
    {
           doSomethingelsebk2();
    }

now the problem is : the function doSomething() in button1's click event must wait both backgrandworker's complete event finish. if i change doSomething() to

    private void backgroundWorker2_RunWorkerCompleted(object sender,RunWorkerCompletedEventArgs e)
    {
           doSomethingelsebk2();
           doSomething();  
    }

then,because there are two thread,i don't know which thread will finish first,so what is the solution

Why not just make backgroundworker2 a normal method and not Async. — CathalMF, Mar 28 '13 at 09:24
Or you could use the AsyncCallBack Delegate http://msdn.microsoft.com/en-GB/library/system.asynccallback(v=vs.90).aspx Here is a good example of using async Callback http://stackoverflow.com/questions/1047662/what-is-asynccallback — CathalMF, Mar 28 '13 at 09:26

score 0 · Answer 1 · answered Mar 28 '13 at 09:29

0

Create 2 flags which represent complete state of 2 BackgroundWorker.

Turn each flag on in the RunWorkerCompleted event, then call doSomething() method.

In doSomething method, check if both flags is on, then continue to do, otherwise, return.

answered Mar 28 '13 at 09:29

Tu Tran

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score 0 · Answer 2 · answered Mar 28 '13 at 13:54

Create 2 AutoResetEvents, set them when each Background worker finishes and wait for them all in the main method with a WaitHandle.

WaitHandle[] handles = new WaitHandle[] { new AutoResetEvent(false), new AutoResetEvent(false)};

private void button1_Click(object sender, EventArgs e)
{
    ParaClass pcs = new ParaClass();
    pcs.strPath = textBox1.Text;
    pcs.sendedGrid = ugSrc;
    this.backgroundWorker1.RunWorkerAsync(pcs);

    ParaClass pcsB = new ParaClass();
    pcsB.strPath = textBox2.Text;
    pcsB.sendedGrid = ultraGrid2;

    this.backgroundWorker2.RunWorkerAsync(pcsB);

    WaitHandle.WaitAll(this.handles);
    doSomething();
}


private void backgroundWorker1_RunWorkerCompleted(object sender,RunWorkerCompletedEventArgs e)
{
       doSomethingelsebk1();
       ((AutoResetEvent)this.handles[0]).Set();
}

private void backgroundWorker2_RunWorkerCompleted(object sender,RunWorkerCompletedEventArgs e)
{
       doSomethingelsebk2();
       ((AutoResetEvent)this.handles[1]).Set();
}

thanks for your reply,i mofidy code as you said,but get a error message:WaitAll for multiple handles on a STA thread is not supported. — user2147152, Mar 28 '13 at 15:26
Hi, you can have a look at: http://stackoverflow.com/questions/4192834/waitall-for-multiple-handles-on-a-sta-thread-is-not-supported — JoanComasFdz, Apr 02 '13 at 09:04

How to wait two BackgrandWorker's RunWorkerCompleted event finished?

2 Answers2