#1,072 – Adding Custom Triggers Related to Keyboard Focus

The default control template for the TextBox control changes the color of the Border around the control when the control gets focus.  It does this by using a trigger hooked to the IsKeyboardFocused property.

You can add your own triggers related to keyboard focus by defining a custom property trigger.  The XAML fragment below defines a new Style element that changes the Background of the control when IsKeyboardFocused is true.

    <Window.Resources>
        <Style x:Key="HoneydewFocus" TargetType="TextBox">
            <Style.Triggers>
                <Trigger Property="IsKeyboardFocused" Value="true">
                    <Setter Property="Background" Value="Honeydew"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>

    <StackPanel>
        <TextBox Margin="5" Width="80"
                 Style="{StaticResource HoneydewFocus}"/>

        <TextBox Margin="5" Width="80"
                 Style="{StaticResource HoneydewFocus}"/>

        <Button Content="Click Me" HorizontalAlignment="Center"
                Padding="12,5" Margin="5" />
    </StackPanel>

As we tab between the two TextBox controls, the one with keyboard focus will have a Honeydew-colored background, as well as the default blue border.