private static void OnIsExpandedPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            ExpanderView view = (d as ExpanderView);

            view.HeaderButton.IsChecked = view.IsExpanded;
        }
        private static void OnContentItemTemplatePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            ExpanderView view = (d as ExpanderView);

            view.ContentListView.ItemTemplate = view.ContentItemTemplate;
        }
 private static void OnDataTemplatePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
 {
     ExpanderView view = (d as ExpanderView);
 }