UIAutomation adding property to cacheRequest

I can add properties to a cacherequest like so:

cacheRequest.Add(AutomationElement.IsControlElementProperty);              
cacheRequest.Add(AutomationElement.IsEnabledProperty);
cacheRequest.Add(AutomationElement.IsOffscreenProperty);

but how would I add the property that is on-screen? E.g. NOT IsOffScreenroperty