title: ViewModel for nested control not refreshing in Catel MVVM for WPF
body: <p>I have a nested control (NC1) which contains 3 instances of NC2.  When the containing view is first opened, NC1 will be null and so the three instances of NC2 will be null.  This appears to work correctly based on debugging through my code and the framework. </p>
  
  <p>When a selection is made in the containing view NC1 is properly set (and the ViewModel is (re)created) and values for its properties (exposed through Fody.Expose) appear in the view.  However, none of the ViewModels for NC2 are (re)created and they do not reflect the values provided by their respective models.</p>
  
  <p>I am not sure exactly what information to provide without uploading a lot of content, so I will take a stab.</p>
  
  <p>In the NC1 view, I have the following</p>
  
  <p>&lt;localViews:NC2 DataContext="NC2Entry1"/&gt;<br/>
  &lt;localViews:NC2 DataContext="NC2Entry2"/&gt;<br/>
  &lt;localViews:NC2 DataContext="NC2Entry3"/&gt;</p>
  
  <p>NC2EntryX are properties on the NC1 ViewModel that return a specific instance of an NC2 model from a list.  The NC2EntryX properties is NOT registered with RegisterProperty.</p>
  
  <p>As a note, I have discovered that I must have an empty parameter constructor for the NC1 and NC2 view models.  If I do not, then I receive a MissingMethod exception when the view model is being created when the TypeFactory attempts to create the ViewModel with the Activator instead of using the injection path.  The injection path is not used because the call at line 591 of TypeFactory returns false because the NC2 model passed is 'not registered'.  (Not sure if it should be or how to make it so.)</p>
  
  <p>I am using Catel version 3.9.0</p>