Question

I have a ListBox with a nested ListBox inside. Both have ObservableCollections as their ItemsSource set with the inner ListBox’s collection being a member of the outer one’s Objects…

The collections are filled by a BackgroundWorker which gathers data from a webservice. I had to change from ObservableCollection to an AsyncObservableCollection in order to be able to add items from within the worker’s code. AsyncObservableCollection code is from here: Have worker thread update ObservableCollection that is bound to a ListCollectionView

My problem is that the inner ListBox keeps to display duplicate items. It seems as if it always duplicates the first item if it decides to duplicate. I have no clue why this happens. With an event listener attached to the CollectionChanged event of the collection I found out that the event is being fired fine once per item.

Do you have any ideas?

Thanks,
Stephan

Answer 1

I found out that the AsyncObservableCollection caused the problems. Obviously it messed up with some events or whatever.
I ended up in adding items to the collection in the worker’s ProgressChanged method.