title: WPF Databinding not updating
body: <p>I'm trying to change the content of a ContentPresenter to one of my View Model class. I manage to have it shown properly,  once I change this content (property) from my model, it doesn't update the ui.</p>
  
  <p>The following lines link my view model classes to their respective ui (setting their data context automatically) : </p>
  
  <pre><code>&lt;DataTemplate DataType="{x:Type vm:WelcomePageViewModel}"&gt;
              &lt;vw:WelcomePage&gt;&lt;/vw:WelcomePage&gt;
   &lt;/DataTemplate&gt;
  
   &lt;DataTemplate DataType="{x:Type vm:UnitPageViewModel}"&gt;
              &lt;vw:UnitPage&gt;&lt;/vw:UnitPage&gt;
   &lt;/DataTemplate&gt;
  </code></pre>
  
  <p>I want to show the ui using binding:</p>
  
  <pre><code>&lt;ContentPresenter Content="{Binding CurrentChildViewModel}" /&gt;
  </code></pre>
  
  <p>So in my ViewModel class, I have a CurrentChildViewModel property, which is an Instance of a closableViewModel. I first assign it in the constructor.</p>
  
  <p>But now when I change the value of my CurrentChildViewModel, it won't update the ui, even if the property is changed in the viewmodel, the first element assigned will stay.</p>
  
  <p>I don't see what I'm doing wrong here. Maybe I'm not using the right architecture (method) to change the content of an element.</p>
  
  <p>Your help would be much appreciated.
  Thanks in advance, </p>
  
  <p>Boris</p>