async Task SetPressImageResource()
{
UIImage source = null;
if (BaseElement.PressedImage != null) {
var handler = BaseElement.PressedImage.GetHandler ();
source = await handler.LoadImageAsync (BaseElement.PressedImage);
base.Control.ShowsTouchWhenHighlighted = false;
}
if (source == null) {
base.Control.ShowsTouchWhenHighlighted = true;
}
Control.SetBackgroundImage (source, UIControlState.Selected);
Control.SetBackgroundImage (source, UIControlState.Highlighted);
}