protected void AddEventListener(INotifyCollectionChanged source, NotifyCollectionChangedEventHandler handler) { if (source == null) { throw new ArgumentException("source"); } if (handler == null) { throw new ArgumentException("handler"); } CollectionChangedEventListener listener = new CollectionChangedEventListener(source, handler); collectionEventListeners.Add(listener); CollectionChangedEventManager.AddListener(source, listener); }