C# : OnClosing takes a while, how can I show a dialog with a marquee progressbar?

I have to do quite some cleanup in my OnClosing handler, which makes it seem like my app is hanging.

How can I show a small dialog with a marquee-style progressbar so users will at least know it's still 'working' ?

Basicly I want to start the dialog, proceed with all my shutdown-procedure开发者_开发技巧s and when that's done, close the progress-dialog.

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There are many ways to achieve this, but one could looke like this:

protected override void OnClosing(CancelEventArgs e)
{
    base.OnClosing(e);

    Form dlg=null;
    ThreadPool.QueueUserWorkItem(state => {
        dlg = new ShuttingDownUI();
        dlg.ShowDialog();
    });

    // do hard work with saving and stuff

    if (dlg != null)
    {
        dlg.BeginInvoke((Action) dlg.Close);
    }
}

In the OnClosing method of your form, open a "shutting down dialog" on a separate thread containing a ProgressBar with its Style property set to Marquee. Then go on and do your saving/closing down procedure, and when you are done, close the "shutting down" dialog.

The important thing is that the form with the marquee must be on a separate thread than the one where the work is being done. Otherwise it will not animate, and the app will still appear as if it is not responding.

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Have you tried something like:

  private void Form1_FormClosing( object sender, FormClosingEventArgs e )
  {
     using ( Form2 myForm2 = new Form2() )
     {
        myForm2.Show();

        //Do your stuff here

        myForm2.Close();
     }
  }