protected virtual void OnItemSelectionChanging(ItemSelectionChangingEventArgs args)
{
if (ItemSelectionChanging != null)
{
ItemSelectionChanging(this, args);
}
}
private void OnItemSelectionChangedCore(RoutedEventArgs args, bool unselected)
{
object item = this.ItemContainerGenerator.ItemFromContainer((DependencyObject)args.OriginalSource);
// When the item is it's own container, "UnsetValue" will be returned.
if (item == DependencyProperty.UnsetValue)
{
item = args.OriginalSource;
}
var itemselectionChangingArgs = new ItemSelectionChangingEventArgs(item, !unselected);
this.OnItemSelectionChanging(itemselectionChangingArgs);
if (itemselectionChangingArgs.Cancel)
{
this.UpdateSelectorItem(item, unselected, false);
return;
}
if (unselected)
{
while (SelectedItems.Contains(item))
{
SelectedItems.Remove(item);
}
}
else
{
if (!SelectedItems.Contains(item))
{
SelectedItems.Add(item);
}
}
}