protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
{
TreeViewItemExtended treeViewItemExtended = (TreeViewItemExtended)element;
treeViewItemExtended.ParentTreeView = this.ParentTreeView;
treeViewItemExtended.ParentTreeViewItem = this;
base.PrepareContainerForItemOverride(element, item);
ParentTreeView.InvokeContainerPrepared(treeViewItemExtended, item);
}