private static void DropItemsPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
DropdownTextBox dt = d as DropdownTextBox;
if (dt != null)
{
IEnumerable oldval, newval;
oldval = (IEnumerable)e.OldValue;
newval = (IEnumerable)e.NewValue;
dt.OnDropItemsChanged(oldval, newval);
}
}
