FormType & method repository - doctrine

Question

I have a problem with my FormType. I want to display data and thanks to the querybuilder make a distinction. Problem when I call my method with a -> select ('t.nomVern') I have "Warning: spl_object_hash () expects parameter 1 to be object, string given" as an error message.
I do not understand why.
My FormType ObservationType:
<?php
namespace ObservationBundle\Form;
use Symfony\Bridge\Doctrine\Form\Type\EntityType;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\DateType;
use Symfony\Component\Form\Extension\Core\Type\HiddenType;
use Symfony\Component\Form\Extension\Core\Type\IntegerType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;
use Vich\UploaderBundle\Form\Type\VichImageType;
use ImportBundle\Repository\TaxrefRepository;
use ImportBundle\Entity\Taxref;
class ObservationType extends AbstractType
{
/**
* #param FormBuilderInterface $builder
* #param array $options
*/
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('date', DateType::class, array(
'widget' => 'single_text',
'html5' => false,
'attr' => array(
'placeholder' => 'Choisir la date de l\'observation',
)
))
->add('latitude', TextType::class, array(
'attr' => array(
'placeholder' => 'Latitude ex : 31.85322'
)
))
->add('longitude', TextType::class, array(
'attr' => array(
'placeholder' => 'Longitude ex : 33.55555'
)
))
->add('nombre', IntegerType::class)
->add('imageFile', VichImageType::class, array(
'required' => false,
'allow_delete' => false, // not mandatory, default is true
'download_link' => false, // not mandatory, default is true
'attr' => array(
'placeholder' => 'Votre image'
)
))
->add('valide', HiddenType::class)
->add('commentaire', HiddenType::class)
->add('gpsAffiche', HiddenType::class)
->add('meteo', HiddenType::class)
->add('saison', HiddenType::class)
->add('typeSaisie', HiddenType::class)
->add('precipitation', HiddenType::class)
->add('periode', HiddenType::class)
->add('environnement', HiddenType::class)
->add('sensibilite', HiddenType::class)
->add('comportement', HiddenType::class)
->add('species', EntityType::class, array(
'label' => 'Espèce observée :',
'class' => 'ImportBundle\Entity\Taxref',
'choice_label' => 'nomVern',
'query_builder' => function(TaxrefRepository $qb){
return $qb->distinctTaxref();
}
))
;
}
/**
* #param OptionsResolver $resolver
*/
public function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults(array(
'data_class' => 'ObservationBundle\Entity\Observation'
));
}
/**
* #return string
*/
public function getBlockPrefix()
{
return 'observationbundle_observation';
}
}
And my repository :
<?php
namespace ImportBundle\Repository;
use Doctrine\DBAL\Query\QueryBuilder;
use Doctrine\ORM\EntityRepository;
use Doctrine\ORM\Tools\Pagination\Paginator;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
class TaxrefRepository extends EntityRepository
{
/**
* Pagination liste des especes
* #param int $page
* #param int $max
* #return Paginator
*/
public function findByPage($page = 1, $max = 8)
{
if(!is_numeric($page)) {
throw new \InvalidArgumentException(
'$page must be an integer ('.gettype($page).' : '.$page.')'
);
}
if(!is_numeric($page)) {
throw new \InvalidArgumentException(
'$max must be an integer ('.gettype($max).' : '.$max.')'
);
}
$dql = $this->createQueryBuilder('t');
$dql->orderBy('t.id', 'DESC');
$firstResult = ($page - 1) * $max;
$query = $dql->getQuery();
$query->setFirstResult($firstResult);
$query->setMaxResults($max);
$paginator = new Paginator($query);
if(($paginator->count() <= $firstResult) && $page != 1) {
throw new NotFoundHttpException('Page not found');
}
return $paginator;
}
/**
* #return \Doctrine\ORM\QueryBuilder
*/
public function distinctTaxref()
{
return $this
->createQueryBuilder('t')
->select('t.nomVern')
->distinct(true)
->orderBy('t.nomVern', 'ASC');
}
}
Thank you in advance for your help and sorry for my bad english :/

Answer 1

Try this part of code
return $this
->createQueryBuilder('t')
->select(array('t.nomVern'))
->distinct(true)
->orderBy('t.nomVern', 'ASC');

Answer 2

I believe that, since you're using EntityType, Symfony expects to have an array of objects, whereas you select a single column which produces an array of strings.
Can you try selecting an object as a whole:
return $this
->createQueryBuilder('t')
->select('t')
->distinct(true)
->orderBy('t.nomVern', 'ASC');
Does this work?