How to properly change the header background of a tabitem

Question

I have a tabitem defined as below

<TabControl x:Name="tbcItems" Background="Transparent" >
    <TabItem x:Name="tbiMacros" Header="MACROS" Foreground="Green" FontWeight="Bold">
        <Grid  Grid.Column="0">
            <ListBox Name="lbxMacro1" HorizontalContentAlignment="Stretch" BorderBrush="White" Foreground="White" Background="Transparent" Margin="10"  HorizontalAlignment="Stretch" VerticalAlignment="Stretch" PreviewMouseLeftButtonDown="ListBox_PreviewMouseLeftButtonDown"/>
        </Grid>
    </TabItem>
</TabControl>

what I want is to change the header of the first macro tabitem

I am only able to change it from code behind with that

tbiMacros.Header = new TextBlock()
{
    Background = Brushes.Red,
    Foreground = Brushes.Green,
    Text = "MACROS",
    Margin = new Thickness(0),
    Padding = new Thickness(0),
    HorizontalAlignment = HorizontalAlignment.Stretch,
    VerticalAlignment = VerticalAlignment.Stretch,
};

but when I do the effect is lousy for it doesn't extend to its full widht/height

thanks for any help

-----ADD------

I have not changed it in the xaml for it has no effect

<TabItem x:Name="tbiMacros" Header="MACROS" Foreground="Green" Background="Red" FontWeight="Bold">
                    ...
</TabItem>

leads to nothings

Answer 1

You have to edit the template to perform this.

1. Right click on a TabControl in the design view
2. Edit additional Template
3. Edit generated item container (ItemContainerStyle)
4. Give a name to the style

Here is the generated code:

<Window.Resources>
    <Style x:Key="FocusVisual">
        <Setter Property="Control.Template">
            <Setter.Value>
                <ControlTemplate>
                    <Rectangle Margin="2" StrokeDashArray="1 2" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" SnapsToDevicePixels="true" StrokeThickness="1"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <LinearGradientBrush x:Key="TabItem.Static.Background" EndPoint="0,1" StartPoint="0,0">
        <GradientStop Color="#F0F0F0" Offset="0.0"/>
        <GradientStop Color="#E5E5E5" Offset="1.0"/>
    </LinearGradientBrush>
    <SolidColorBrush x:Key="TabItem.Static.Border" Color="#ACACAC"/>
    <LinearGradientBrush x:Key="TabItem.MouseOver.Background" EndPoint="0,1" StartPoint="0,0">
        <GradientStop Color="#ECF4FC" Offset="0.0"/>
        <GradientStop Color="#DCECFC" Offset="1.0"/>
    </LinearGradientBrush>
    <SolidColorBrush x:Key="TabItem.MouseOver.Border" Color="#7EB4EA"/>
    <SolidColorBrush x:Key="TabItem.Selected.Background" Color="Red"/>
    <SolidColorBrush x:Key="TabItem.Selected.Border" Color="#ACACAC"/>
    <SolidColorBrush x:Key="TabItem.Disabled.Background" Color="#F0F0F0"/>
    <SolidColorBrush x:Key="TabItem.Disabled.Border" Color="#D9D9D9"/>
    <Style x:Key="TabControlItemContainerStyle" TargetType="{x:Type TabItem}">
        <Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
        <Setter Property="Foreground" Value="Black"/>
        <Setter Property="Background" Value="{StaticResource TabItem.Static.Background}"/>
        <Setter Property="BorderBrush" Value="{StaticResource TabItem.Static.Border}"/>
        <Setter Property="Margin" Value="0"/>
        <Setter Property="Padding" Value="6,2,6,2"/>
        <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
        <Setter Property="VerticalContentAlignment" Value="Stretch"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type TabItem}">
                    <Grid x:Name="templateRoot" SnapsToDevicePixels="true">
                        <Border x:Name="mainBorder" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="1,1,1,0" Margin="0">
                            <Border x:Name="innerBorder" Background="{StaticResource TabItem.Selected.Background}" BorderBrush="{StaticResource TabItem.Selected.Border}" BorderThickness="1,1,1,0" Margin="-1" Opacity="0"/>
                        </Border>
                        <ContentPresenter x:Name="contentPresenter" ContentSource="Header" Focusable="False" HorizontalAlignment="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{Binding VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Left"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Background" TargetName="mainBorder" Value="{StaticResource TabItem.MouseOver.Background}"/>
                            <Setter Property="BorderBrush" TargetName="mainBorder" Value="{StaticResource TabItem.MouseOver.Border}"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,1,0,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,1,0,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Bottom"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Background" TargetName="mainBorder" Value="{StaticResource TabItem.MouseOver.Background}"/>
                            <Setter Property="BorderBrush" TargetName="mainBorder" Value="{StaticResource TabItem.MouseOver.Border}"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,0,1,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,0,1,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Right"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Background" TargetName="mainBorder" Value="{StaticResource TabItem.MouseOver.Background}"/>
                            <Setter Property="BorderBrush" TargetName="mainBorder" Value="{StaticResource TabItem.MouseOver.Border}"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="0,1,1,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="0,1,1,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Top"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Background" TargetName="mainBorder" Value="{StaticResource TabItem.MouseOver.Background}"/>
                            <Setter Property="BorderBrush" TargetName="mainBorder" Value="{StaticResource TabItem.MouseOver.Border}"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,1,1,0"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,1,1,0"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Left"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Opacity" TargetName="contentPresenter" Value="0.56"/>
                            <Setter Property="Background" TargetName="mainBorder" Value="{StaticResource TabItem.Disabled.Background}"/>
                            <Setter Property="BorderBrush" TargetName="mainBorder" Value="{StaticResource TabItem.Disabled.Border}"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,1,0,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,1,0,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Bottom"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Opacity" TargetName="contentPresenter" Value="0.56"/>
                            <Setter Property="Background" TargetName="mainBorder" Value="{StaticResource TabItem.Disabled.Background}"/>
                            <Setter Property="BorderBrush" TargetName="mainBorder" Value="{StaticResource TabItem.Disabled.Border}"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,0,1,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,0,1,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Right"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Opacity" TargetName="contentPresenter" Value="0.56"/>
                            <Setter Property="Background" TargetName="mainBorder" Value="{StaticResource TabItem.Disabled.Background}"/>
                            <Setter Property="BorderBrush" TargetName="mainBorder" Value="{StaticResource TabItem.Disabled.Border}"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="0,1,1,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="0,1,1,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Top"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Opacity" TargetName="contentPresenter" Value="0.56"/>
                            <Setter Property="Background" TargetName="mainBorder" Value="{StaticResource TabItem.Disabled.Background}"/>
                            <Setter Property="BorderBrush" TargetName="mainBorder" Value="{StaticResource TabItem.Disabled.Border}"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,1,1,0"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,1,1,0"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" Value="false"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Left"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,1,0,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,1,0,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" Value="true"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Left"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Panel.ZIndex" Value="1"/>
                            <Setter Property="Margin" Value="-2,-2,0,-2"/>
                            <Setter Property="Opacity" TargetName="innerBorder" Value="1"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,1,0,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,1,0,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" Value="false"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Bottom"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,0,1,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,0,1,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" Value="true"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Bottom"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Panel.ZIndex" Value="1"/>
                            <Setter Property="Margin" Value="-2,0,-2,-2"/>
                            <Setter Property="Opacity" TargetName="innerBorder" Value="1"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,0,1,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,0,1,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" Value="false"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Right"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="0,1,1,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="0,1,1,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" Value="true"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Right"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Panel.ZIndex" Value="1"/>
                            <Setter Property="Margin" Value="0,-2,-2,-2"/>
                            <Setter Property="Opacity" TargetName="innerBorder" Value="1"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="0,1,1,1"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="0,1,1,1"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" Value="false"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Top"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,1,1,0"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,1,1,0"/>
                        </MultiDataTrigger>
                        <MultiDataTrigger>
                            <MultiDataTrigger.Conditions>
                                <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" Value="true"/>
                                <Condition Binding="{Binding TabStripPlacement, RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}" Value="Top"/>
                            </MultiDataTrigger.Conditions>
                            <Setter Property="Panel.ZIndex" Value="1"/>
                            <Setter Property="Margin" Value="-2,-2,-2,0"/>
                            <Setter Property="Opacity" TargetName="innerBorder" Value="1"/>
                            <Setter Property="BorderThickness" TargetName="innerBorder" Value="1,1,1,0"/>
                            <Setter Property="BorderThickness" TargetName="mainBorder" Value="1,1,1,0"/>
                        </MultiDataTrigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Window.Resources>

Then search for <SolidColorBrush x:Key="TabItem.Selected.Background" Color="#FFFFFF"/> and replace the color value by what feats your needs.

The style will only apply on the selected TabControl.

• To apply it to many TabControl: move it to application resources and reuse it.

• To apply it to all TabControl:

  • Remove the ItemContainerStyle="{StaticResource TabControlItemContainerStyle}" attribute
  • Add a global style that set the ItemContainerStyle at application level:

<Application.Resources>
    <!-- ...  -->

    <Style TargetType="TabControl" BasedOn="{StaticResource {x:Type TabControl}}">
        <Style.Setters>
            <Setter Property="ItemContainerStyle" Value="{StaticResource TabControlItemContainerStyle}" />
        </Style.Setters>
    </Style>
</Application.Resources>

A working demo is available here.