全球appBar，为特定页面添加其他按钮到这个appbar

Question

我添加一个appbar，在App.xaml.cs中有3个按钮放在每个页面上，但我有一个页面，我想另外添加另一个按钮。

我做了什么，它是从App.xaml.cs中获取3个默认按钮的appbar，然后添加我的其他按钮。问题是当它被添加时，当我改变页面，我添加的按钮保持可见...因此，这是对象的引用问题，因为每个页面引用同一个appbar。

我不知道是否有可能复制这个appbar只有4个按钮的页面...（Icloneable？但我不知道如何：/）你怎么看？ 我还应该提到一些按钮使用导航去另一页。

这里是我的代码：

App.xaml.cs

private ApplicationBar _appBar; 
public ApplicationBar AppBar { get { return _appBar; } } //property called in other page 

//Method called in the constructor 
private void BuildLocalizedApplicationBar() 
    { 
     // Set the page's ApplicationBar to a new instance of ApplicationBar. 
     _appBar = new ApplicationBar(); 

     // Create a new button and set the text value to the localized string from AppResources. 
     var appBarButtonScan = new ApplicationBarIconButton(new Uri("/Assets/AppBar/White/appbar.qr.png", UriKind.Relative)); 
     appBarButtonScan.Click += AppBarButtonScanOnClick; 
     appBarButtonScan.Text = AppResources.Scan; 

     var appBarButtonSearch = new ApplicationBarIconButton(new Uri("/Assets/AppBar/White/appbar.search.png", UriKind.Relative)); 
     appBarButtonSearch.Click += AppBarButtonSearchOnClick; 
     appBarButtonSearch.Text = AppResources.Search; 

     var appBarButtonFacebook = new ApplicationBarIconButton(new Uri("/Assets/AppBar/White/appbar.facebook.png", UriKind.Relative)); 
     appBarButtonFacebook.Click += AppBarButtonFacebookOnClick; 
     appBarButtonFacebook.Text = AppResources.MyAccount; 

     _appBar.Buttons.Add(appBarButtonScan); 
     _appBar.Buttons.Add(appBarButtonSearch); 
     _appBar.Buttons.Add(appBarButtonFacebook); 

     // Create a new menu item with the localized string from AppResources. 
     ApplicationBarMenuItem appBarMenuSettings = new ApplicationBarMenuItem(AppResources.SettingsTitle); 
     _appBar.MenuItems.Add(appBarMenuSettings); 
    } 

在网页，我想有另外一个按钮：

private void BuildLocalizedApplicationBar() 
    { 
     App _app = Application.Current as App; //in my page, it's an attribute that I initialize in my constructor. 
     ApplicationBar = _app.AppBar; //get the appbar with 3 buttons from App.xaml.cs 

     // Create new buttons and set the text value to the localized string from AppResources. 
     ApplicationBarIconButton appBarButtonTagPlace = new ApplicationBarIconButton(new Uri("/Assets/AppBar/White/appbar.heart.outline.png", UriKind.Relative)); 
     appBarButtonTagPlace.Text = AppResources.TagThisPlaceTitle; 
     appBarButtonTagPlace.Click += AppBarButtonTagPlaceOnClick; 


     ApplicationBar.Buttons.Add(appBarButtonTagPlace); 
    } 

预先感谢您

Answer 1

您可以在离开具有额外按钮的页面时移除该按钮。

protected override void OnNavigatingFrom(NavigatingCancelEventArgs e) 
{ 
    ApplicationBar.Buttons.Remove(appBarButtonTagPlace); 
    base.OnNavigatedFrom(e); 
}