/// <summary> /// This method is invoked when the Items property changes. /// </summary> protected override void OnItemsChanged(NotifyCollectionChangedEventArgs e) { switch (e.Action) { case NotifyCollectionChangedAction.Remove: ParentTreeView?.ClearObsoleteItems(e.OldItems); break; case NotifyCollectionChangedAction.Reset: case NotifyCollectionChangedAction.Replace: case NotifyCollectionChangedAction.Add: case NotifyCollectionChangedAction.Move: break; default: throw new NotSupportedException(); } }