title: assign a xaml file in a frame source dynamically
body: <p>I have this code in a xaml file now in a event handler code i want to assign a xaml file in a frame source dynamically</p>
  
  <p>the code in xaml file is ..</p>
  
  <pre><code>&lt;navigation:Frame Name="ProjectTab" Grid.Column="1" Grid.Row="2" Source="/ProjectTab.xaml"/&gt;
  </code></pre>
  
  <p>here this assignment of source  is working but how to do that in a .cs file.</p>
  
  <p>ProjectTab.Sourse=???</p>