Creating closeable tabitems for use in CompositeWPF

Using a tabcontrol as a region for views in a CompositeWPF application is one thing, making them closeable can be a bit trickier. The sample in this article will show how you can modify a tabcontrol to allow closeable items.

Step 1: Make the custom header template and tabitem style

The first step is to modify the look of a tabitem header so it contains a close button while leaving room for the header content defined on the tab item. The XAML content required for this looks like the following:

<TabControl>
    <TabControl.Resources>        
        <DataTemplate x:Key=&quot;CustomTabHeader&quot;>
            <StackPanel Orientation=&quot;Horizontal&quot;>
                <ContentPresenter>
                    <ContentPresenter.Content>
                        <Binding Path=&quot;Header&quot;>
                            <Binding.RelativeSource>
                                <RelativeSource Mode=&quot;FindAncestor&quot; 
                                                AncestorType=&quot;{x:Type TabItem}&quot;/>
                            </Binding.RelativeSource>
                        </Binding>
                    </ContentPresenter.Content>
                </ContentPresenter>
                <Button Margin=&quot;8,0,0,0&quot; Command=&quot;local:Commands.CloseTabItem&quot; CommandParameter=&quot;{Binding 
                                       RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type TabItem}}}&quot; 
                        HorizontalContentAlignment=&quot;Center&quot; 
                        VerticalContentAlignment=&quot;Center&quot;>
                    <Grid>
                        <Canvas Width=&quot;8&quot; Height=&quot;8&quot;>
                            <Line X1=&quot;2&quot; X2=&quot;6&quot; Y1=&quot;2&quot; Y2=&quot;6&quot; 
                                  Stroke=&quot;Black&quot; StrokeThickness=&quot;1&quot;/>
                            <Line X1=&quot;6&quot; X2=&quot;2&quot; Y1=&quot;2&quot; Y2=&quot;6&quot; 
                                  Stroke=&quot;Black&quot; StrokeThickness=&quot;1&quot;/>
                        </Canvas>
                    </Grid>
                </Button>
            </StackPanel>
        </DataTemplate>    
        <Style TargetType=&quot;TabItem&quot;>
            <Style.Setters>
                <Setter Property=&quot;HeaderTemplate&quot; 
                        Value=&quot;{StaticResource CustomTabHeader}&quot;/>
            </Style.Setters>
        </Style>
    </TabControl.Resources>
</TabControl>

Step 2: Closing tabitems

The second step is writing a little bit of code to close tabitems when the command is fired.

private void OnCloseTabItemExecute(object sender, ExecutedRoutedEventArgs e)
{
    TabItem parent = e.Parameter as TabItem;

    if (parent != null)
    {
        FrameworkElement view = (parent as TabItem).Content as FrameworkElement;
        string regionName = RegionManager.GetRegionName(view);

        _regionManager.Regions[regionName].Remove(view);
    }
}

The first thing to do is find the tabitem that is quietly wrapped around the view that was added to the tabcontrol. This is done through a recursive search for parent framework elements until the tabitem is found. After that its a matter of retrieving the value of the RegionName attached property and removing the tabitem content from the region.

Conclusion

While a custom may look prettier over time it’s really not a requirement to make closable views in a compositeWPF application. Thanks to the powerful styling and templating features in WPF you can make the tabcontrol as fancy as you like without making it overly complex to work with.

 

— Update : The sample didn't work as expected. I have updated the sample code and made sure it works now. Please notify me if any more issues arise.