title: WPF + Caliburn Micro: how to catch Window Close event?
body: <p>I am new in Caliburn Micro and learn it from <a href="http://buksbaum.us/2010/08/01/caliburn-micro-hello-world/">this helloworld example</a>. In the example there are only 2 views (.xaml) of type Application and UserControl, and 1 view model.</p>
  
  <p>I avoid to use code behind. Therefore I have only view and view model. I want to know <strong>how to catch the window close event of my helloworld application</strong> so I can handle it in view model. My target: when user is going to close the app by pressing close [x] button on top-right corner the app gives feedback to the user.<br>
  I have read about IViewAware and IScreen, but I find no specific example related to my question.</p>
  
  <p>A simple sample code for view and view model are highly appreciated. Thanks in advance.</p>
  
  <p>PS. I use VS2013, C#.</p>