symfony3 CollectionType OneToMany

Question

我有2个实体：person和emailaddress

class Person
{

/**
     * @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)
     */
    private $name;

    /**
     * @var Emailaddress[]
     * @ORM\OneToMany(targetEntity="Emailaddress", mappedBy="person", cascade={"ALL"})
     *
     */
    private $emails;


    public function __construct() {
        $this->emails = new ArrayCollection();
    }

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

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

        return $this;
    }

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

    /**
     * Add email
     *
     * @param \AppBundle\Entity\Emailaddress $email
     *
     * @return Person
     */
    public function addEmail(\AppBundle\Entity\Emailaddress $email)
    {
        $this->emails[] = $email;
        $email->setPerson($this);

        return $this;
    }

    /**
     * Remove email
     *
     * @param \AppBundle\Entity\Emailaddress $email
     */
    public function removeEmail(\AppBundle\Entity\Emailaddress $email)
    {
        $this->emails->removeElement($email);
    }

    /**
     * Get emails
     *
     * @return \Doctrine\Common\Collections\Collection
     */
    public function getEmails()
    {
        return $this->emails;
    }
}

class Emailaddress
{
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var string
     *
     * @ORM\Column(name="emailaddress", type="string", length=100)
     */
    private $emailaddress;

    /**
     * @var Person
     * @ORM\ManyToOne(targetEntity="Person", inversedBy="emails")
     * @ORM\JoinColumn(name="person_id", referencedColumnName="id")
     */
    private $person;

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

    /**
     * Set emailaddress
     *
     * @param string $emailaddress
     *
     * @return Emailaddress
     */
    public function setEmailaddress($emailaddress)
    {
        $this->emailaddress = $emailaddress;

        return $this;
    }

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

    /**
     * Set person
     *
     * @param \AppBundle\Entity\Person $person
     *
     * @return Emailaddress
     */
    public function setPerson(\AppBundle\Entity\Person $person = null)
    {
        $this->person = $person;

        return $this;
    }

    /**
     * Get person
     *
     * @return \AppBundle\Entity\Person
     */
    public function getPerson()
    {
        return $this->person;
    }
}

在EmailaddressType中我有：

$builder->add('email');

在PersonType中：

$builder->add('name')
        ->add('emails', CollectionType::class, array(
                'entry_type'   => EmailAddressType::class,
                'allow_add' => true,
     ));

现在，当在电子邮件字段上生成表单时，不会显示任何内容。 如何生成电子邮件字段？

由于