title: What is the proper way of handling logoff / shutdown / restart when the application has unsaved data?
body: <p>In WPF App.Current.SessionEnding must return in a few seconds, otherwise the "application does not respond" window appears. So the user can't be asked in this event handler to save his data, because the user's response takes longer than a few seconds.</p>
  
  <p>I thought a solution would be to cancel the logoff / shutdown / restart, and resume it when the user answered to the file save dialog.</p>
  
  <pre><code>    ReasonSessionEnding _reasonSessionEnding;
  
      App.Current.SessionEnding +=
          new SessionEndingCancelEventHandler(Current_SessionEnding);
  
      void Current_SessionEnding(object sender, SessionEndingCancelEventArgs e)
      {
          if (_dataModified)
          {
              e.Cancel = true;
              _reasonSessionEnding = e.ReasonSessionEnding;
              Dispatcher.CurrentDispatcher.BeginInvoke(new Action(EndSession));
          }
      }
  
      void EndSession()
      {
          if (SaveWithConfirmation()) // if the user didn't press Cancel
              //if (_reasonSessionEnding = ReasonSessionEnding.Logoff)
                  // logoff
              //else
                  // shutdown or restart ?
      }
  </code></pre>
  
  <p>The problem is that ReasonSessionEnding does not tell me if Windows was shutting down or restarting (it does not differentiate between the two).</p>
  
  <p>So, what should my program do on the session ending event ?
  Should it even do anything, or doing nothing on this event is the standard ?</p>
  
  <p>The user is asked to save his changes in my main form's OnClosing method, so he does not lose data, but I think that the "application does not respond" window does not suggest a normal workflow.</p>
  
  <p>Canceling the shutdown is not desired I guess, because some of the other programs have been shut down already.</p>