Question

Below is a style I use for buttons in my application. Now I’m trying to change the background color of the Border element that has the name "Background" when the user clicks the button with the left mouse button.

How do I do that?

<Style TargetType="{x:Type Button}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Button}">
                <Border BorderBrush="#6e6964" BorderThickness="1" CornerRadius="1" Margin="{TemplateBinding Margin}" SnapsToDevicePixels="True">
                    <Border BorderBrush="White" BorderThickness="1" CornerRadius="1" SnapsToDevicePixels="True">
                        <Border Padding="12,4,12,4" SnapsToDevicePixels="True" Name="Background">
                            <Border.Background>
                                <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                                    <GradientStop Color="White" Offset="0"/>
                                    <GradientStop Color="#f1f1f1" Offset="1"/>
                                </LinearGradientBrush>
                            </Border.Background>
                            <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" />
                        </Border>
                    </Border>
                </Border>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsMouseOver" Value="True">
                        <Setter Property="Background" TargetName="Background">
                            <Setter.Value>
                                <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                                    <GradientStop Offset="0" Color="#edf8fb"/>
                                    <GradientStop Offset="1" Color="#e2edf0"/>
                                </LinearGradientBrush>
                            </Setter.Value>
                        </Setter>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Answer 1

You just need the following property trigger:

<ControlTemplate.Triggers>
    <Trigger Property="IsPressed" Value="True">
        <Setter Property="Background" TargetName="Background" Value="Red"/>
    </Trigger>
</ControlTemplate.Triggers>