// Creates a PropertyNames list from the data definition.
 private static function PropertyNames(LJCDataManager $manager)
 {
   // See constructor for how to create $manager.
   $methodName = "PropertyNames()";
   $propertyNames = $manager->PropertyNames();
 
   $result = "";
   foreach ($propertyNames as $propertyName)
   {
     if (strlen(trim($result)) > 0)
     {
       $result .= ",";
     }
     $result .= $propertyName;
   }
 
   // result:
   // ID,Name
 }