title: If the user logs on successfully, then I want to show the main window, if not, I want to exit the application
body: <p>Stupidly simple question I can't figure out.</p>
  
  <p>I have a WPF application, and I want to display a Logon dialog box first (before the main window shows up). </p>
  
  <p>If the user logs on successfully, then I want to show the main window, if not, I want to exit the application.</p>
  
  <p>How does one do this correctly?</p>