OnItemsChanged
ItemsControl class in Silverlight Beta2 has added protected virtual method OnItemsChanged. This method is invoked when Items Property changes. This could be used to add a custom behavior when items are added or removed. Here is the quick sample.
I wanted Listbox where when a selected item is removed, it selects the next item in the list.
CustomListBox
1: public class MyListBox: ListBox
2: {
3: protected override void OnItemsChanged(System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
4: {
5: base.OnItemsChanged(e);
6: if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
7: {
8: if (e.OldStartingIndex < Items.Count)
9: SelectedItem = Items[e.OldStartingIndex];
10: else
11: SelectedItem = Items[Items.Count - 1];
12: }
13: }
14: }
Here is the sample that compares the behavior of default listbox and customlist box.
