public ElementCollectionChangedEventArgs(IElementCollection collection, CollectionChangeAction action, IEnumerable <CollectionChangeItemInfo> changedItems) { Collection = collection; Action = action; ChangedItems = changedItems.ToArray(); ElementType = CollectionExtensions.GetCollectionType(collection.GetType()); if (ElementType == null) { ElementType = ChangedItems[0].Element.GetElementType(); } }