Filtering an ObservableCollection?

Question

When I bind a ListBox directly to an ObservableCollection I get the real-time updates displayed in my ListBox, but as soon as I add other LINQ methods in the mix my ListBox

Answer 1

Why it does not work:

listBox1.ItemsSource = Words.Where(w => w.Contains(":"));

Your are not binding the ObservableCollection but the IEnumerable generated by Linq. This new "list" does not notify the ListBox about changes in the list.