I'm simply trying to check if a page has an associated image, eg:

@{
   if (d.HasProperty("mainImage") {
       <p>Do one thing...</p>
 } else {
       <p>Do another...</p>
   }
}

This one obviosuly doesn't work, but I've tried:

if (String.IsNullOrEmpty(d.GetProperty("mainImage").ToString())==false){

... and a bunch of others, but noting works! Every page *has* the property, but some may not have an image uploaded (I'm using Upload data type, not Media library). In XSLT I'd simply check for an empty string being returned to indicate that no image had been uploaded for the current page...

Any ideas?