private static void OnNumColumnsUpdated(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            TablePanel t = (TablePanel)d;

            t.InvalidateMeasure();
        }
        private static void InRowSpacingUpdated(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            TablePanel t = (TablePanel)d;

            t.InvalidateMeasure();
        }