static private void container_SelectionChanged(ListBox container, ListBoxItem lbi)
{
ScrollViewer sv = container.GetFirstVisualChild<ScrollViewer>();
if (sv == null)
return;
if (sv.ComputedVerticalScrollBarVisibility != Visibility.Visible)
return;
ScrollContentPresenter sp = sv.GetFirstVisualChild<ScrollContentPresenter>();
GeneralTransform childTransform = lbi.TransformToAncestor(sp);//sv
Rect rectangle = childTransform.TransformBounds(new Rect(new Point(0, 0), lbi.RenderSize));
//Check if the elements Rect intersects with that of the scrollviewer's
Rect result = Rect.Intersect(new Rect(new Point(0, 0), sp.RenderSize), rectangle);
//if result is Empty then the element is not in view
if (result != rectangle)
{
double Heigth = rectangle.Top;
sv.SmoothToVertical(Heigth + sv.VerticalOffset, TimeSpan.FromSeconds(0.5));
}
}