Detecting KeyDown in an entry?

Hi,

I'd like to detect when the backspace keyboard button is pressed in an Entry even when there is no text in the entry. I've tried creating a custom renderer and overriding OnKeyDown but it doesn't seem to do anything. In my custom android renderer that extends Entry:

public override bool OnKeyDown(Keycode keyCode, KeyEvent e)
{
    Console.WriteLine("A key was pressed");
    if (keyCode == Keycode.Del)
    {
        // do stuff here
    }
    return base.OnKeyDown(keyCode, e);
}

Unfortunately this doesn't seem to do anything. How can I achieve this?