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());
}