Each "View" is an independent XAML file. I'd like to be able to set up the triggers in those files, looking at the ListBoxItem's IsSelected property, in order to control the visibility of the various controls within.The template to override the ListBoxItem follows:    I modified the ContentPresenter in the following way in order to test out using the "FindAncestor" RelativeSource:
         
              
           
      
     This works, but when I move similar code into the XAML file representing a View it no longer sees the trigger. For example:
         
              
           
          
              
           
          
              
               
           
      
     How can I detect, preferably from the View's XAML file, when the ListBoxItem has been selected?

I notice that DataTrigger.Value property is missing in UserContrl's Style. With the following changes, I think your code would work.