Gets an object related to this instance by a foreign key relationship.
Use this for 1:? (one:zero-or-one) or 1:1 relationships, which you can distinguish by setting the nullability of the field representing the foreign key.
xPDOObject|null &getOne ( string $alias, [object $criteria = null], [boolean|integer $cacheFlag = true] )
Echo the email of a modUser with ID 1, which has a related object called modUserProfile, that has a field called "email" - set as "email@example.com" for this user.
$user = $modx->getObject('modUser',1); $profile = $user->getOne('Profile'); echo $profile->get('email'); // prints "firstname.lastname@example.org"