Increasing WPF ObservableCollection performance

Answer 1

You could probably inherit from ObservableCollection<T> (or directly implement INotifyCollectionChanged) to add BeginUpdate and EndUpdate methods. Changes made between calls to BeginUpdate and EndUpdate would be queued, then combined into one (or several if there are separate ranges) NotifyCollectionChangedEventArgs object that would be passed to the handlers of the CollectionChanged event when EndUpdate is called.

Answer 2

You can find a Thread safe observable collection here. Make your Observable collection thread safe and bind it to listbox.

Answer 3

I have removed the CollectionViewSource and the grouping and the items are copied over in 1/2 a second, but with the grouping on it can take up to a minute because virtualisation does not work with the grouping.

I will need to decide whether to use the CollectionViewSource