GridView Refresh UI fail

[Neogeo]

The GridView is binding to a collectionview from the viewmodel:

 ItemsSource="{Binding Path=dataitemscv, NotifyOnSourceUpdated=True}"

which dataitemscv is a ICollectionView

I have checked dataitemscv is updated.

The collectionchanged event did fire with action as reset

I have tried to Refresh() the collectionview in viewmodel

I have tried to Rebind the GridView in code behind

nothing will update the UI, any suggestions?