title: Use binding to change usercontrol in a grid
body: <p>I'm creating a WPF application, which has a main screen in which other screens are loaded. </p>
  
  <p>The main screen can be seen as a header/footer template where the central part is replaced depending on what I need to show at that moment. (It's a 3 row grid where the <code>usercontrol</code> should be put in row 1). This has a <code>viewmodel</code> that is changing header/footer status.</p>
  
  <p>I have implemented those changing parts (row 1) as usercontrols. </p>
  
  <p>Now I am wondering if there is any way to use binding (to something..) so that I can change the loaded <code>usercontrol</code> and not do it from code behind as I'm doing it now.</p>
  
  <p>If this is going completely against MVVM principles, please give me hints on how I should handle this.</p>
  
  <p>Thanks!!</p>