// a version of IsAncestorOf that stops looking when it finds an ancestor
// of the given type
internal static bool IsAncestorOf(DependencyObject ancestor, DependencyObject descendant, Type stopType)
{
if (ancestor == null)
{
throw new ArgumentNullException("ancestor");
}
if (descendant == null)
{
throw new ArgumentNullException("descendant");
}
VisualTreeUtils.EnsureVisual(ancestor);
VisualTreeUtils.EnsureVisual(descendant);
// Walk up the parent chain of the descendant until we run out of parents,
// or we find the ancestor, or we reach a node of the given type.
DependencyObject current = descendant;
while ((current != null) && (current != ancestor) && !stopType.IsInstanceOfType(current))
{
Visual visual;
Visual3D visual3D;
if ((visual = current as Visual) != null)
{
current = visual.InternalVisualParent;
}
else if ((visual3D = current as Visual3D) != null)
{
current = visual3D.InternalVisualParent;
}
else
{
current = null;
}
}
return(current == ancestor);
}
