【Windows Phone 8】ApplicationBarIconButton的添加及移除

【代码】

public partial class ProductDetailView : PhoneApplicationPage
    {
        private IList<IApplicationBarIconButton> appbarButtons;
        private ApplicationBarIconButton consultButton;
        private ApplicationBarIconButton favoriteButton;
        private ApplicationBarIconButton shareButton;
        private ApplicationBarIconButton catalogButton;
        private ApplicationBarIconButton cartButton;
　　　　 private bool isLoaded = false;
        
        public ProductDetailView()
        {
            InitializeComponent();
        }

        private void root_Loaded_1(object sender, RoutedEventArgs e)
        {
            if (!isLoaded)
            {
　　　　　　　　　 // 初始化按钮
                appbarButtons = this.ApplicationBar.Buttons as IList<IApplicationBarIconButton>;
                favoriteButton = appbarButtons[0] as ApplicationBarIconButton;
                shareButton = appbarButtons[1] as ApplicationBarIconButton;
                catalogButton = appbarButtons[2] as ApplicationBarIconButton;
                cartButton = appbarButtons[3] as ApplicationBarIconButton;
                isLoaded = true;
                ChangeAppbar();
            }
        }

        private void AddAppbarButton()
        {
            consultButton = new ApplicationBarIconButton(new Uri("/Resources/Images/ApplicationBar2/zixun1.png", UriKind.Relative));
            consultButton.Text = "咨询";
            consultButton.Click += consultButton_Click;
        }

　　　　

 void consultButton_Click(object sender, EventArgs e)
 {

 }

 　　　　private void ChangeAppbarBtn()
        {
            if (isLoaded)
            {
                if (...)
                {
　　　　　　　　　　　　// 只有一个咨询按钮
                    appbarButtons.Clear();
                    appbarButtons.Add(consultButton);
                }
                else if (...)
                {
                    appbarButtons.Clear();
　　　　　　　　　　　　// 恢复初始的4个按钮
                    appbarButtons.Add(favoriteButton);
                    appbarButtons.Add(shareButton);
                    appbarButtons.Add(catalogButton);
                    appbarButtons.Add(cartButton);
                }
            }
        }
　　}