*/
public function preProcess() {
$this->_eventId = CRM_Utils_Request::retrieve('id', 'Positive', $this, TRUE);
- $this->_action = CRM_Utils_Request::retrieve('action', 'String', $this, FALSE);
+ $this->_action = CRM_Utils_Request::retrieve('action', 'Alphanumeric', $this, FALSE, CRM_Core_Action::ADD);
//CRM-4320
$this->_participantId = CRM_Utils_Request::retrieve('participantId', 'Positive', $this);