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