ToggleButton Trigger IsChecked Doesn't Change Background

Question

I have a ToggleButton with a red background. I need to set a green background when the toggle button is checked.

I've tried this:

<ToggleButton Content="Test 001" Name="btn03" Height="20">
    <ToggleButton.Style>
        <Style TargetType="ToggleButton">
            <Setter Property="Background" Value="#ff0000" />
            <Style.Triggers>
                <Trigger Property="IsChecked" Value="True">
                    <Setter Property="Background" Value="#00ff00" />
                </Trigger>
            </Style.Triggers>
        </Style>
    </ToggleButton.Style>
</ToggleButton>

But instead a green color I get a light blue color (I think is the default color of my system).

What I'm doing wrong and how to fix it?

Answer 1

WPF 4.0 doesen't allow this. Look here for a different approach:

<Grid>
    <Grid.Resources>
        <Style x:Key="ToggleButtonStyle" TargetType="{x:Type ToggleButton}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                        <Border HorizontalAlignment="Center" VerticalAlignment="Center" x:Name="border" Background="Red">
                            <ContentPresenter/>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsChecked" Value="true">
                                <Setter Property="Background" TargetName="border" Value="Green"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Grid.Resources>

    <ToggleButton Content="ToggleButton" Style="{StaticResource ToggleButtonStyle}"/>
</Grid>