WPF Style BasedOn does not work

Question

I have made a style RadioButtonToggleButtonStyle as below.

  <ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                        xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
                        d1p1:Ignorable="d" 
                        xmlns:d1p1="http://schemas.openxmlformats.org/markup-compatibility/2006"                    
                        xmlns:local="clr-namespace:TeachpendantControl">

        <Style x:Key="RadioButtonToggleButtonStyle" 
               BasedOn="{StaticResource {x:Type ToggleButton}}"
               TargetType="{x:Type RadioButton}">
            <Style.Triggers>
                <Trigger Property="IsChecked" Value="True">
                    <Setter Property="Background" Value="Gold"/>
                </Trigger>
            </Style.Triggers>
        </Style>   
    </ResourceDictionary>

I use it like this below.

 <ListBox  Grid.Column="0" Grid.Row="0" Grid.RowSpan="10" ItemsSource="{Binding LeftPaneViewModelInfoItems, UpdateSourceTrigger=PropertyChanged}" Background="Transparent" SelectedItem="{Binding SelectedViewModelInfoItem}">
                    <ListBox.ItemContainerStyle>
                        <Style TargetType="{x:Type ListBoxItem}">
                            <Setter Property="Background" Value="Transparent" />
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type ListBoxItem}">
                                        <ContentPresenter />
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </ListBox.ItemContainerStyle>
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <RadioButton 
                                Content="{Binding Text}"                                     
                                GroupName="DisplayPage"
                                IsChecked="{Binding IsSelected, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}}}"
                                Style="{StaticResource RadioButtonToggleButtonStyle}"                                     
                                >                                    
                            </RadioButton>
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>

The CheckBoxes show up as ToggleButtons when I run the application (but it shows up as CheckBoxes in Design mode).

But I don't get a gold background when the CheckBox (styled as ToggleButton) is checked. Also Visual Studio (2015) complains in the resource file saying "The resource {x:Type ToggleButton}" could not be resolved.

Can anyone provide an explanation of why this does not work (and how to solve it)

Answer 1

You need to modify the ControlTemplate to be able to change the Background of a ToggleButton.

The default ControlTemplate contains hardcoded values that take precedence over the value that you specify in your Style.

You can copy the default template into your project by right-clicking on a ToggleButton in design mode in Visual Studio or in Blend and choose Edit Template->Edit a Copy and then edit it as per your requirements. Try this:

<Style x:Key="RadioButtonToggleButtonStyle" TargetType="{x:Type ToggleButton}">
    <Style.Resources>
        <Style x:Key="FocusVisual">
            <Setter Property="Control.Template">
                <Setter.Value>
                    <ControlTemplate>
                        <Rectangle Margin="2" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <SolidColorBrush x:Key="Button.Static.Background" Color="#FFDDDDDD"/>
        <SolidColorBrush x:Key="Button.Static.Border" Color="#FF707070"/>
        <SolidColorBrush x:Key="Button.MouseOver.Background" Color="#FFBEE6FD"/>
        <SolidColorBrush x:Key="Button.MouseOver.Border" Color="#FF3C7FB1"/>
        <SolidColorBrush x:Key="Button.Pressed.Background" Color="#FFC4E5F6"/>
        <SolidColorBrush x:Key="Button.Pressed.Border" Color="#FF2C628B"/>
        <SolidColorBrush x:Key="Button.Disabled.Background" Color="#FFF4F4F4"/>
        <SolidColorBrush x:Key="Button.Disabled.Border" Color="#FFADB2B5"/>
        <SolidColorBrush x:Key="Button.Disabled.Foreground" Color="#FF838383"/>
    </Style.Resources>
    <Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
    <Setter Property="Background" Value="{StaticResource Button.Static.Background}"/>
    <Setter Property="BorderBrush" Value="{StaticResource Button.Static.Border}"/>
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
    <Setter Property="BorderThickness" Value="1"/>
    <Setter Property="HorizontalContentAlignment" Value="Center"/>
    <Setter Property="VerticalContentAlignment" Value="Center"/>
    <Setter Property="Padding" Value="1"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ToggleButton}">
                <Border x:Name="border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" SnapsToDevicePixels="true">
                    <ContentPresenter x:Name="contentPresenter" Focusable="False" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                </Border>
                <ControlTemplate.Triggers>
                    <Trigger Property="Button.IsDefaulted" Value="true">
                        <Setter Property="BorderBrush" TargetName="border" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
                    </Trigger>
                    <Trigger Property="IsMouseOver" Value="true">
                        <Setter Property="Background" TargetName="border" Value="{StaticResource Button.MouseOver.Background}"/>
                        <Setter Property="BorderBrush" TargetName="border" Value="{StaticResource Button.MouseOver.Border}"/>
                    </Trigger>
                    <Trigger Property="IsPressed" Value="true">
                        <Setter Property="Background" TargetName="border" Value="{StaticResource Button.Pressed.Background}"/>
                        <Setter Property="BorderBrush" TargetName="border" Value="{StaticResource Button.Pressed.Border}"/>
                    </Trigger>
                    <Trigger Property="IsEnabled" Value="false">
                        <Setter Property="Background" TargetName="border" Value="{StaticResource Button.Disabled.Background}"/>
                        <Setter Property="BorderBrush" TargetName="border" Value="{StaticResource Button.Disabled.Border}"/>
                        <Setter Property="TextElement.Foreground" TargetName="contentPresenter" Value="{StaticResource Button.Disabled.Foreground}"/>
                    </Trigger>
                    <Trigger Property="IsChecked" Value="true">
                        <Setter Property="Background" TargetName="border" Value="Gold" />
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>