private async Task InsertTodoItem(TodoItem todoItem)
        {
            // This code inserts a new TodoItem into the database. When the operation completes
            // and Mobile Services has assigned an Id, the item is added to the CollectionView
            await todoTable.InsertAsync(todoItem);
            items.Add(todoItem);

             await SyncAsync(); // offline sync
        }
        private async Task UpdateCheckedTodoItem(TodoItem item)
        {
            // This code takes a freshly completed TodoItem and updates the database. When the MobileService 
            // responds, the item is removed from the list 
            await todoTable.UpdateAsync(item);
            items.Remove(item);
            ListItems.Focus(Windows.UI.Xaml.FocusState.Unfocused);

             await SyncAsync(); // offline sync
        }
 private async void ButtonSave_Click(object sender, RoutedEventArgs e)
 {
     var todoItem = new TodoItem { Text = TextInput.Text };
     await InsertTodoItem(todoItem);
 }