public override void ViewDidLoad()
        {
            base.ViewDidLoad ();

            itemController = new TodoSource (ItemsTable, todoTable);
            itemController.IsUpdatingChanged += (sender, e) =>
            {
                RefreshButton.Enabled =
                AddButton.Enabled =
                    !itemController.IsUpdating;
            };

            ItemsTable.Source = itemController;
        }
        public override void ViewDidLoad()
        {
            base.ViewDidLoad();

            itemController = new TodoSource(ItemsTable, todoTable);
            itemController.IsUpdatingChanged += (sender, e) =>
            {
                RefreshButton.Enabled =
                    AddButton.Enabled =
                        !itemController.IsUpdating;
            };

            ItemsTable.Source = itemController;
        }