private ChildType FindVisualChild<ChildType>(DependencyObject obj)

            where ChildType : DependencyObject

        {

            for (int i = ; i < VisualTreeHelper.GetChildrenCount(obj); i++)

            {

                DependencyObject child = VisualTreeHelper.GetChild(obj, i);

                if (child != null && child is ChildType)

                {

                    return child as ChildType;

                }

                else

                {

                    ChildType childOfChild = FindVisualChild<ChildType>(child);

                    if (childOfChild != null)

                    {

                        return childOfChild;

                    }

                }

            }

            return null;

        }