title: Windows Phone inherited application page: designer error but compiles
body: <p>I have a XAML Page which inherits from a userdefined class of mine:</p>
  
  <pre><code>&lt;xpap:GenericListPage 
  x:Class="my.View.ListPage"
  xmlns:xpap="clr-namespace:my.View.Generic" ... /&gt;
  </code></pre>
  
  <p>Initially I wanted to use a generic base class for my XAML page, but that was no possible (at least in WP7; <strong>is it possible in WP8 to use generic base classes for pages?</strong>). So I ended up with this work-around (ExtendedPhoneApplicationPage inherits from PhoneApplicationPage adds extra functionality/behaviour that all my pages like ListPage etc. should have in commen):</p>
  
  <pre><code>namespace my.View
  {
      namespace Generic
      {
          public partial class GenericListPage : 
              ExtendedPhoneApplicationPage&lt;ListViewModel&gt;
          {
              ...
          }
      }
  
      public partial class ListPage : Generic.GenericListPage
      {
          ...
      }
  
      public class ExtendedPhoneApplicationPage&lt;T&gt; : 
          PhoneApplicationPage where T : class, IViewModelBase
      {
          ...
      }
  }
  </code></pre>
  
  <p>This worked fine all together until I installed the WP8 SDK (as far as I can remember). The designer says "invalid markup" and there is an error saying: "The name "GenericListPage" does not exist in the namespace "clr-namespace:my.View.Generic"."</p>
  
  <p>The strange part is, that the solution compiles and can be deployed on the emulator. Anyone know why or how to eliminate the error?</p>