How do I create a WPF rounded container that clips children?

Question

The following piece of code is supposed to draw a menu bar inside a rounded container. You\'ll notice that the bottom is rounded, but the corners of the menu aren\'t. I fo

Answer 1

Chris Cavanagh has a blog post about rounding controls. It should help you achieve what you want.

Edit: Below is the code from that blog.

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Background="Black">
    <!-- Rounded yellow border -->
    <Border BorderThickness="3" BorderBrush="Yellow" CornerRadius="10" Padding="2" HorizontalAlignment="Center" VerticalAlignment="Center">
        <Grid>
            <!-- Rounded mask (stretches to fill Grid) -->
            <Border Name="mask" Background="White" CornerRadius="7"/>
            <!-- Main content container -->
            <StackPanel>
                <!-- Use a VisualBrush of 'mask' as the opacity mask -->
                <StackPanel.OpacityMask>
                    <VisualBrush Visual="{Binding ElementName=mask}"/>
                </StackPanel.OpacityMask>
                <!-- Any content -->
                <Image Source="https://chriscavanagh.files.wordpress.com/2006/12/chriss-blog-banner.jpg"/>
                <Rectangle Height="50" Fill="Red"/>
                <Rectangle Height="50" Fill="White"/>
                <Rectangle Height="50" Fill="Blue"/>
            </StackPanel>
        </Grid>
    </Border>
</Page>

All it does is include a ‘mask’ Border element as a sibling of the content you want to clip. In the content it uses a VisualBrush bound to that mask. The mask will be automatically sized to your content, so it’s a nice "set and forget" solution