Detect when a form has been closed c#

Question

I have a WinForm that I create that shows a prompt with a button. This is a custom WinForm view, as a message box dialog was not sufficient.

I have a background work

Answer 1

Make sure your background worker supports cancellation and as others have pointed out use the form closed event handler. This code should point you in the right direction:

using(CustomForm myForm = new CustomForm())
{
  myForm.FormClosed += new FormClosedEventHandler(ChildFormClosed);
  myForm.Show(theFormOwner);
  myForm.Refresh();


  while(aBackgroundWorker.IsBusy)
  {
    Thread.Sleep(1);
    Application.DoEvents();
  }
}

void ChildFormClosed(object sender, FormClosedEventArgs e)
{
    aBackgroundWorker.CancelAsync();
}