从数据库字段类型日期获取值

I am looking for to display some dates in a field embedded to a form. In fact, the fields is correct when I passed my query in the repository and display it with the twig template. But when I get the same query and embed in the form, an exception is coming...

May be, I have a problem because it's date.

The field in my Form :

->add('dateEnd', 'entity', array(
                'class' => 'BackBundle:PackagesDatesPrices',
                'property' => 'DateEnd',
                'query_builder' => function(EntityRepository $er) use ($id) {
                    return $er->createQueryBuilder('a')
                        ->innerjoin('a.package', 'c', 'WITH', 'a.package = c.id')
                        ->addSelect('a')
                        ->add('where', 'c.id = :id')
                        ->add('orderBy', 'a.price ASC')
                        ->setParameter('id', $id)
                        ;
                },
            ))

In my repository :

public function getAdvertWithDatesPrices($id)
    {
        $qb = $this->createQueryBuilder('a')
            ->innerjoin('a.package', 'c', 'WITH', 'a.package = c.id')
            ->addSelect('a')
            ->add('where', 'c.id = ?1')
            ->add('orderBy', 'a.price ASC')
            ->setParameter(1, $id);
        ;

        return $qb
            ->getQuery()
            ->getResult()
            ;
    }

And the error :

Thank you for your advices.