private static void OnSelectedItemKeyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            GalleryToolBehavior behavior = d as GalleryToolBehavior;

            if (behavior != null)
            {
                behavior.OnSelectedItemKeyChanged((string)e.OldValue, (string)e.NewValue);
            }
        }
        private static void OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            GalleryToolBehavior behavior = d as GalleryToolBehavior;

            if (behavior != null)
            {
                behavior.OnItemsSourceChanged((IEnumerable)e.OldValue, (IEnumerable)e.NewValue);
            }
        }