ArcGISPortalViewer.Controls.GalleryPreviewControl.OnItemsSourcePropertyChanged C# (CSharp) Method

        private static void OnItemsSourcePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var ctrl = d as GalleryPreviewControl;
            if (e.OldValue != null)
            {
                if (e.OldValue is INotifyCollectionChanged)
                {
                    (e.OldValue as INotifyCollectionChanged).CollectionChanged -= ctrl.GalleryPreviewControl_CollectionChanged;
                }
            }

            if (e.NewValue != null)
            {
                if (e.NewValue is INotifyCollectionChanged)
                {
                    (e.NewValue as INotifyCollectionChanged).CollectionChanged += ctrl.GalleryPreviewControl_CollectionChanged;
                }
            }
            ctrl.Children.Clear();
            ctrl.InvalidateMeasure();
        }