Global appBar, add other buttons to this appbar for a specific page

Question

I add an appbar with 3 buttons in App.xaml.cs to put it on each page but I have a page where I would like to add another button in addition.

What I do, it's I get the appbar with my 3 defaults buttons from App.xaml.cs, then I add my other button. The problem is when it's added and when I change the page, the button I added stay visible... Thus, it's a problem with the reference of the object because each page reference the same appbar.

I wonder if it's possible to copy this appbar for only the page with 4 buttons...(Icloneable? but I don't know how :/) What do you think? I should also mention that some buttons use navigation to go another page.

Here is my code:

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);
    }

In the page where I would like to have one button in addition:

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);
    }

Thank you in advance

Answer 1

You could remove the button when leaving the page that has the extra button.

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