In a STA thread: Form.Hide() = BackgroundWorker event not firing??

Question

Hi, I want to hide the main window while the backgroundworker is working, but When I set the main form as this.Hide() before the backgroundworker.RunWorkerAsync(), Both ProgressChanged and RunWorkerCompleted are not firing. How can I achieve this? thanks.

More code: ProgressChanged and RunWorkerCompleted are firing with:

private void button1_Click(object sender, EventArgs e)
 {
    backgroundworker.RunWorkerAsync();
 }

ProgressChanged and RunWorkerCompleted are not firing with:

private void button1_Click(object sender, EventArgs e)
 {
    this.Hide();
    backgroundworker.RunWorkerAsync();
 }

Sorry: More information: The form is used in a shared (COM) Outlook add-in.

In outlook there is a button, click this button to load the form, the problem happens when I show my form in a new thread like this:

private void MyButton_Click(CommandBarButton cmdBarbutton, ref bool cancel)
{              
    System.Threading.Thread tt = new System.Threading.Thread(new System.Threading.ThreadStart(showwindow));
    tt.SetApartmentState(System.Threading.ApartmentState.STA);
    tt.Start();               
}


private void showwindow()
{
    GUIForm = new MyForm();           
    GUIForm.ShowDialog();
}

If I just load the form, no problem:

private void MyButton_Click(CommandBarButton cmdBarbutton, ref bool cancel)
{              
   showwindow();              
}


private void showwindow()
{
    GUIForm = new MyForm();           
    GUIForm.ShowDialog();
}

How can I put the GUI in a new thread and still have my backgroundwork events within the GUI?

Answer 1

Cannot reproduce this.

It works on my computer.

You are probably doing something inside your DoWork (or maybe ProgressChanged) that needs a visible Window.

---

In your extended question the Bgw doesn't seem to play a role anymore...

You cannot simply start (show) a Window in another Thread, you need to run a MessagePump on the Thread as well.

For the Thread scenario, you could use:

private void showwindow()
{
    GUIForm = new MyForm();           
    //GUIForm.ShowDialog();
    Application.Run(GUIForm);
}

But that will run the Form Modeless, not Modal.