title: uwp MVVM ContentDialog with enabled primary button when CanExecute is false
body: <p>I try to build a ContentDialog similar to the example in <a href="https://docs.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.contentdialog" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.contentdialog</a> with mvvm.</p>
  
  <p>For the CanExecute validation I have created a derived ContentDialog class described in <a href="https://social.msdn.microsoft.com/Forums/en-US/6d5d6fd9-5f03-4cb6-b6c0-19ca01ddaab8/uwpcontentdialog-buttons-do-not-respect-canexecute?forum=wpdevelop" rel="nofollow noreferrer">https://social.msdn.microsoft.com/Forums/en-US/6d5d6fd9-5f03-4cb6-b6c0-19ca01ddaab8/uwpcontentdialog-buttons-do-not-respect-canexecute?forum=wpdevelop</a></p>
  
  <p>This works but how can I enable the button so it is clickable for the CanExecute validation.</p>