public static void PairExpanded(this TreeViewItem item, UIElement pairToObject, RoutedEvent pairToExpandEvent, RoutedEvent pairToCollapseEvent, DependencyProperty pairToProperty)
{
item.AddSelfExpanded((sender, args) => pairToObject.SetValue(pairToProperty, true));
item.AddSelfCollapsed((sender, args) => pairToObject.SetValue(pairToProperty, false));
pairToObject.SetValue(pairToProperty, item.IsExpanded);
pairToObject.AddHandler(pairToExpandEvent, new RoutedEventHandler((sender, args) => item.IsExpanded = true));
pairToObject.AddHandler(pairToCollapseEvent, new RoutedEventHandler((sender, args) => item.IsExpanded = false));
}
