Why is my XAML ToggleButton invisible to the code-behind?

Question

I have a ToggleButton in MainPage.xaml:

<ToggleButton x:Name="ColorToggle" Background="{Binding Background, ElementName=LayoutRoot}" ToolTipService.ToolTip="Change Toolbar Color">

...yet when I try to access it from MainPage.xaml.cs:

private void SaveAppBarColorSelected(object sender, TappedRoutedEventArgs e)
{
    PhotraxUtils.SetLocalSetting(PhotraxConsts.APPBARBUTTON_COLOR, ColorToggle.Background.ToString());
}

...I get, "The name 'ColorToggle' does not exist in the current context"

Why is that?

Yes - ToggleButton is in MainPage.xaml, and the method is in MapnPage.xaml.cs. It is declared within a ControlTemplate in the xaml. — B. Clay Shannon-B. Crow Raven, Nov 16 '14 at 05:38
Set its DataContext to your View to reach outside of the ControlTemplate it sits in via relativesource or directly. ;) — Chris W., Nov 16 '14 at 08:46
"MainPage", not "MapnPage" (although that typo does sort of make sense). — B. Clay Shannon-B. Crow Raven, Nov 16 '14 at 14:45

score 1 · Accepted Answer · answered Nov 16 '14 at 11:09

Only controls from the root context are available in code-behind. If you place your named control inside a template, it won't be available. You can traverse the controls tree using VisualTreeHelper and other methods in this case.

Or better yet, just use MVVM.

Why is my XAML ToggleButton invisible to the code-behind?

1 Answers1