ObservableCollection : calling OnCollectionChanged with multiple new items

Question

please note that I am trying to use NotifyCollectionChangedAction.Add action instead of .Reset. the latter does work, but it is not very efficient with large collections.

Answer 1

I believe you need to cast it to an IList:

base.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, (IList)_cachedItems));