带有formType的Symfony枚举类型

我有一个symfony实体,它有一个枚举类型字段,我想为它生成一个表单类型。

这是我的实体:

<?php

namespace EvalBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * SessionEvaluation
 *
 * @ORM\Table(name="session_evaluation")
 * @ORM\Entity(repositoryClass="EvalBundle\Repository\SessionEvaluationRepository")
 */
class SessionEvaluation
{
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var string
     *
     * @ORM\Column(name="name", type="string", length=255, unique=true)
     */
    private $name;

    /**
     * @var \DateTime
     *
     * @ORM\Column(name="startDate", type="datetime")
     */
    private $startDate;

    /**
     * @var \DateTime
     *
     * @ORM\Column(name="endDate", type="datetime")
     */
    private $endDate;

    /**
     * @var string
     *
     * @ORM\Column(name="type", type="string", columnDefinition="enum('annual', 'intermediate')")
     */
    private $type;

    /**
     * One SessionEvaluation has Many PerformanceEvaluation.
     * @ORM\OneToMany(targetEntity="PerformanceEvaluation", mappedBy="sessionEvaluation")
     */
    private $performanceEvaluations;

    /**
     * One SessionEvaluation has Many Evaluation.
     * @ORM\OneToMany(targetEntity="Evaluation", mappedBy="sessionEvaluation")
     */
    private $evaluations;

    /**
     * Get id
     *
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Set name
     *
     * @param string $name
     *
     * @return SessionEvaluation
     */
    public function setName($name)
    {
        $this->name = $name;

        return $this;
    }

    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * Set startDate
     *
     * @param \DateTime $startDate
     *
     * @return SessionEvaluation
     */
    public function setStartDate($startDate)
    {
        $this->startDate = $startDate;

        return $this;
    }

    /**
     * Get startDate
     *
     * @return \DateTime
     */
    public function getStartDate()
    {
        return $this->startDate;
    }

    /**
     * Set endDate
     *
     * @param \DateTime $endDate
     *
     * @return SessionEvaluation
     */
    public function setEndDate($endDate)
    {
        $this->endDate = $endDate;

        return $this;
    }

    /**
     * Get endDate
     *
     * @return \DateTime
     */
    public function getEndDate()
    {
        return $this->endDate;
    }

    /**
     * Set type
     *
     * @param string $type
     *
     * @return SessionEvaluation
     */
    public function setType($type)
    {
        $this->type = $type;

        return $this;
    }

    /**
     * Get type
     *
     * @return string
     */
    public function getType()
    {
        return $this->type;
    }

    public function __toString() {
        return $this->name;
    }
}

<?php

namespace EvalBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
use Symfony\Component\Form\Extension\Core\Type\DateType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class SessionEvaluationType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('Name', TextType::class, array(
            'attr'=> array('class'=>'form-control')
        ))
                ->add('startDate', DateType::class, array(
                    'format' => 'yyyy MM dd'
                ))
                ->add('endDate')
                ->add('type', ChoiceType::class, array(
                    'choices' => array(
                        'Annuel' => true,
                        'Itérmidaire' => false,
                    ),
                    'attr' => array('class' => 'dropdown')

                ))
            ->add('Lancer', SubmitType::class, array(
                'attr' => array('class' => 'btn btn-primary')));

    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'EvalBundle\Entity\SessionEvaluation'
        ));
    }

    /**
     * {@inheritdoc}
     */
    public function getBlockPrefix()
    {
        return 'evalbundle_sessionevaluation';
    }


}

枚举类型为的字段为:type