Is it possible to NotifyChanged on an ObservableCollection property via CollectionChanged event?

Question

Is it possible for me to have an ObservableCollection as a property in a class but subscribe to it's CollectionChanged event and call OnPropertyChanged on the ObservableCollection property as to update a UI binding to the collection? –

Answer 1

Yes, but usually you wouldn't want to do something like that because of the overhead. If you use controls with an ItemsSource they know how to handle CollectionChanged without re-creating everything.

Answer 2

Instead of binding to the collection and using a converter you can expose a read-only ItemNames property. In the Items.CollectionChanged event handler you raise a PropertyChanged event for the ItemNames property

public class ViewModel
{

      public ViewModel()
      {
           Items = new ObservableCollection<Item>();
           Items.CollectionChanged += (o, e) => NotifyPropertyChanged("ItemNames");
      }
      public ObservableCollection<Item> Items { get; private set; }
      public string ItemNames { get { return String.Join(",", Items); } }
}