Removing link from page selector with an event handler

I have a sfPageField control on my widget designer to select a page to redirect to upon a button press. With that, in the designer, I want to give the user the option to remove the link. However, in the event handler for the button press, I can't quite figure out how to clear out the PageField control of the link. What properties would I need to clear out? I've already tried resetting a handful of properties to no avail. I'd appreciate any help. 

Thanks.