private void delete_list_Click(object sender, RoutedEventArgs e)
        {
            ListModel delete_list = all_lists_grid.SelectedItem as ListModel;

            if (delete_list != null)
            {
                ListController controller = new ListController();
                bool           result     = controller.DeleteList(delete_list.List_id);

                if (result)
                {
                    all_lists.Remove(delete_list);
                }
            }
        }