/// <summary>
 /// Sets the Behavior property.  
 /// </summary>
 private static void SetBehavior(DependencyObject d, CommandBehaviorBinding value)
 {
     d.SetValue(BehaviorProperty, value);
 }
 //tries to get a CommandBehaviorBinding from the element. Creates a new instance if there is not one attached
 private static CommandBehaviorBinding FetchOrCreateBinding(DependencyObject d)
 {
     CommandBehaviorBinding binding = CommandBehavior.GetBehavior(d);
     if (binding == null)
     {
         binding = new CommandBehaviorBinding();
         CommandBehavior.SetBehavior(d, binding);
     }
     return binding;
 }