[TYPO3-dev] An object of class "[...]ObjectStorage" could not be converted to a plain value

[Carsten Pohl]

Hi,

i got an error after calling the persistance manager to receive the last added uid of an object ('$inserat') via getUid.

Controller
$this->inseratRepository->add($inserat);
$persistenceManager = $this->objectManager->get('Tx_Extbase_Persistence_Manager');
$persistenceManager->persistAll();

Error Message:
#1274799934: An object of class "TYPO3\CMS\Extbase\Persistence\ObjectStorage" could not be converted to a plain value.

TYPO3 6.1

Can anyone help? Thanks in advance!