<?php

public MyFinalAction($userValue){
    // Object Model Erzeugen
    $dataObject = $this->objectManager->get('Tx_UserMyExtension_Domain_Model_MyModel');

    // Properties Setzen
    $dataObject->setPropertyOne($userValue);
    $dataObject->setPropertyTwo($dataBaseValue);

    // Validation
    $validatorResolver = $this->objectManager->get('Tx_Extbase_Validation_ValidatorResolver');
    $validatorConjunction = $validatorResolver->getBaseValidatorConjunction('Tx_UserKimAersignup_Domain_Model_KimSignup');
    $result = $validatorConjunction->isValid($dataObject);
    if($result === true){
        // Persist the New Object
        $this->dataObjectRepository->add($dataObject);
    }{
        // add a Custom Error Message for Frontend error Reporting
        $this->addCustomError('pseudoProperty','Model Validation has Failed',4711);
        // redirect to Error Action
        $this->errorAction();
    }

}

/**
 * Creates a Custom Error for Attributes wich are Evaluated in the Controller
 * @param string $propertyName name of the property with an error
 * @param string $message      the default message if not Translated
 * @param integer $code        the error code needs to be unique
 */
protected function addCustomError($propertyName,$message,$code){
    $error = $this->objectManager->get('Tx_Extbase_MVC_Controller_ArgumentError', $propertyName);
    $propertyErrors = array();
    $propertyErrors[$propertyName] = $this->objectManager->get('Tx_Extbase_Validation_Error',$message,$code);
    $error->addErrors($propertyErrors);
    $this->propertyMapper->getMappingResults()->addError($error,$propertyName);
    $this->hasCustomError = true;
}

?>