title: WinForms; detecting form closed from another form
body: <p>Is it possible to detect a form closing from another form.
  For example.
  If I had a mainForm that opens subForm, can I detect within the mainForm that the subForm has closed and execute code?</p>
  
  <p>I understand I could create an event handler within the subForm, but this is not really what I'm after because what I'm about to do after the subForm closes, is within the mainForm (changes to mainForm).</p>