Prevent Ctrl + C Ctrl + V for TextBox ?

How to prevent Ctrl + C, Ctrl + V for TextBox ?

I use Keydown event

void TextBox_KeyDown(object sender, Windows.UI.Xaml.Input.KeyRoutedEventArgs e)
{
    e.Handled = true;
}

But it don't work.

If can prevent Ctrl + C, Ctrl + V for entire control in my application.

Thanks for your help.