将UserControl中的子元素焦点传递给WPF中的父元素

<UserControl ...>
    <Grid>
       <Button Content="Click me" Focusable="False" />
    </Grid>
</UserControl>

protected override void OnKeyDown(KeyEventArgs e)
{
    base.OnKeyDown(e);
    if (e.Key == Key.Enter || e.Key == Key.Space)
    {
        e.Handled = true;
        TraversalRequest request = new TraversalRequest(FocusNavigationDirection.Next);
        this.MoveFocus(request);
    }
}