private static void OnSelectedItemsPropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
        {
            RadGridView grid = dependencyObject as RadGridView;
            INotifyCollectionChanged selectedItems = e.NewValue as INotifyCollectionChanged;

            if (grid != null && selectedItems != null)
            {
                MySelectedItemsBindingBehavior behavior = new MySelectedItemsBindingBehavior(grid, selectedItems);
                behavior.Attach();
            }
        }
        private static void OnSelectedItemsPropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
        {
            RadGridView grid = dependencyObject as RadGridView;
            INotifyCollectionChanged selectedItems = e.NewValue as INotifyCollectionChanged;

            if (grid != null && selectedItems != null)
            {
                MySelectedItemsBindingBehavior behavior = new MySelectedItemsBindingBehavior(grid, selectedItems);
                behavior.Attach();
            }
        }