How can I apply MahApps style to my own WPF control?

Question

Normally, when I set Header of the TabItem to some string, MahApps styles are applied to the TabItem Header.

However, I programmatically created custom TabItem, it's header is not a string but a StackPanel and all styling from MahApps is lost. How can I re-apply MahApps styles to my custom TabItem Header?

TabItem tabItem = new TabItem();

StackPanel tabItemHeader = new StackPanel();
tabItemHeader.Orientation = Orientation.Horizontal;
var tabTitle = new Label() {Content = "Userstory"};
var closeButton = new Button() {Content = "x"}; 
tabItemHeader.Children.Add(tabTitle);
tabItemHeader.Children.Add(closeButton);

tabItem.Header = headerStackPanel;

Answer 1

You should do this with the power of XAML and styles. Here is a short sample what you can do:

Put this style to Window resources or App resources.

<Style x:Key="CustomTabItemStyle" TargetType="{x:Type TabItem}" BasedOn="{StaticResource MetroTabItem}">
    <Setter Property="HeaderTemplate">
        <Setter.Value>
            <DataTemplate>
                <StackPanel Orientation="Horizontal">
                    <ContentPresenter Content="{TemplateBinding Content}" />
                    <Button Margin="2" VerticalAlignment="Top" Width="{Binding RelativeSource={RelativeSource Self}, Path=ActualHeight}" Content="x" />
                </StackPanel>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

and use it at your TabItems

<TabItem Header="Userstory" Style="{StaticResource CustomTabItemStyle}">
    <!-- your tab content -->
</TabItem>

Benefit of using styles is, that you can do/change what you want...

Hope this helps!