public ListBindViewModel() { Items = new BindableList <ItemViewModel>(); SelectedDropDownIndex = new ObservableProperty <int>(0); DropdownData = new List <Dropdown.OptionData>() { new Dropdown.OptionData("回锅肉"), new Dropdown.OptionData("梅菜扣肉"), new Dropdown.OptionData("水煮肉片"), new Dropdown.OptionData("辣子鸡丁"), new Dropdown.OptionData("鱼香肉丝") }; Items.AddListener((list) => OnUpdateItem()); }