WPF rectangle – round just top corners

February 23, 2023 by Tarik

The problem you’ve got is that the rectangle is “overflowing” the rounded corners of your border.

A rectangle can’t have individually rounded corners, so if you just put the background colour on the border and remove the rectangle:

<Border BorderThickness="1" Grid.Row="0" Grid.ColumnSpan="2"
        CornerRadius="50,50,0,0" BorderBrush="Black" Background="#FF5A9AE0">
</Border>

You’ll get your desired effect.