With the RTM release of Visual Studio 2012 the Visual Studio team made some improvements to the various AppBar button styles. One of these awesome improvements was to add support for ToggleButtons. Now you can use any of these out-of-the-box styles with Buttons AND ToggleButtons. This is pretty awesome… Except for the fact that the style is missing a required TextBlock. This TextBlock toggles the color of the button. Without it you do not get a visual indication that the ToggleButton is checked. Even worse, is that the application crashes when the ToggleButton is checked.
To fix this, open the StandardStyles.xaml file and go to the AppBarButtonStyle. Insert the following line directly under the “BackgroundGlyph” TextBlock
<TextBlock x:Name="BackgroundCheckedGlyph" Visibility="Collapsed" Text="" FontFamily="Segoe UI Symbol" FontSize="53.333" Margin="-4,-19,0,0" Foreground="{StaticResource AppBarItemForegroundThemeBrush}"/>
After inserting that line, the Grid within the StackPanel should look like:
<Grid Width="40" Height="40" Margin="0,0,0,5" HorizontalAlignment="Center">
<TextBlock x:Name="BackgroundGlyph" Text="" FontFamily="Segoe UI Symbol" FontSize="53.333" Margin="-4,-19,0,0" Foreground="{StaticResource AppBarItemBackgroundThemeBrush}"/>
<TextBlock x:Name="BackgroundCheckedGlyph" Visibility="Collapsed" Text="" FontFamily="Segoe UI Symbol" FontSize="53.333" Margin="-4,-19,0,0" Foreground="{StaticResource AppBarItemForegroundThemeBrush}"/>
<TextBlock x:Name="OutlineGlyph" Text="" FontFamily="Segoe UI Symbol" FontSize="53.333" Margin="-4,-19,0,0"/>
<ContentPresenter x:Name="Content" HorizontalAlignment="Center" Margin="-1,-1,0,0" VerticalAlignment="Center"/>
</Grid>
Now your app will not crash with that ToggleButton!
Next, read Part 2 to fix the VisualState of the ToggleButton.