private void ButtonAllSuppliers_Click(object sender, RoutedEventArgs e)
        {
            this.topgrid.Visibility          = Visibility.Collapsed;
            this.mainscrollviewer.Visibility = Visibility.Collapsed;

            SupplierList x = new SupplierList();

            UserPages.Children.Clear();
            UserPages.Children.Add(x);
        }