title: How to close a WPF child window using MVVM without any MVVM frameworks?
body: <p>I am very new to MVVM and WPF.</p>
  
  <p>The application I have created has two buttons, openWindow and closeWindow.
  I managed to hook up the openWindow using the ICommand and go it to open a new window :)
  My question is how when I press that closeWindow, do I close that opened window?</p>
  
  <p>I am not using any MVVM frameworks like MVVM Light etc.</p>
  
  <p>Much appreciated.</p>