As I realized, you bound the ItemsSource
property of your control to an empty collection and, filled your collection afterwards. Possible reason of the disappearance of the items is that the binding isn't notified about the collection's changes.
In order to let the binding to be notified about the collection's changes, you have to bind the ItemsSource
property to a collection that implements INotifyCollectionChanged. For that purpose you can use ObservableCollection.
You can replace the EntitySet
property in your view-model with a corresponding ObservableCollection
property.