Android TimePicker OK-Button pressed event

Hello,
how do I catch the OK-Button pressed Event in Android TimePicker custom renderer?

    public class TimerTimePickerRenderer : TimePickerRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.TimePicker> e)
        {
            base.OnElementChanged(e);

            if (Control != null)
            {
                //When OK Button is pressed:
                //MessagingCenter.Send("Droid", "TimeChanged")
            }
        }
    }