public static void PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            TPageControl control = d as TPageControl;

            if (control == null)
            {
                return;
            }

            List <UserControl> children = e.NewValue as List <UserControl>;

            if (children == null)
            {
                return;
            }

            control.AddControls(children);
        }
        private static void RightWidthChange(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            TPageControl pageControl = (TPageControl)sender;

            pageControl.RightGrid.Width = new GridLength(pageControl.RightWidth);
        }