forms - Symfony CollectionType : Merge new entries

Question

我的 symfony 表单表示一个实体 Mail，它与另一个名为 Attachment 的实体具有一对多关系。因此，MailType 表单包含一个 CollectionType 字段，用于嵌入其 AttachmentType 表单:

$builder
    ->add('attachments', CollectionType::class, [
        'entry_type' => AttachmentType::class,
        'allow_add' => true,
        'allow_delete' => false,
        'by_reference' => false,
    ]);

我的 View 只会将新附件发送到我的 Symfony 后端。因此，当将表单数据存储到数据库中时，我只想添加邮件的新附件，而不触及任何现有附件。

不幸的是，Symfony/Doctrine 的行为有所不同:如果表单数据中包含 n 个附件，则 n 第一个现有附件将被这些新附件覆盖:

existing attachments (in DB): [old1, old2, old3]
new attachments (contained by HTTP request): [new1, new2]
desired result in DB: [old1, old2, old3, new1, new2]
actual result in DB: [new1, new2, old3]

我怎样才能实现这个目标？我认为 by_reference => false 会导致调用 addAttachment 方法，因此我也希望它能够开箱即用。

我的Mail实体代码:

class Mail {
    /**
     * @ORM\OneToMany(targetEntity="AppBundle\Entity\Attachment", mappedBy="mail", cascade={"persist", "remove"})
     */
    protected $attachments;

    ...

    public function addAttachment(\AppBundle\Entity\ttachment $attachment) {
        $attachment->setMail($this);
        $this->attachments[] = $attachment;
        return $this;
    }
}

我的 Controller 代码处理表单:

    // $mail = find mail in database
    $form = $this->createForm(MailType::class, $mail);
    $form->handleRequest($request);

    if ($form->isValid()) {
        $mail = $form->getData();
        $em = $this->getDoctrine()->getManager();
        $em->persist($mail);
        $em->flush();
    }

Answer 1

有几种方法可以满足您的需求。最简单的方法是向表单字段提供空数据或新的附件实体:

$builder
        ->add('attachments', CollectionType::class, [
            'entry_type' => AttachmentType::class,
            'allow_add' => true,
            'allow_delete' => true,
            'by_reference' => false,
            'data' => [new Attachment()] // or add more or []
        ]);

然后在您的邮件实体中:

public function addAttachment(Attachment $attachment) {
    $attachment->setMail($this);
    $this->attachments[] = $attachment;
    return $this;
}

public function removeAttachment(Attachment $attachment) {
    return $this;
}

如果您将removeAttachment用于某些其他功能，并且想要实际删除附件，则可以利用表单字段的property_path设置:

'property_path' => 'appendAttachments'

并创建addAppendAttachment和removeAppendAttachment:

public function addAppendAttachment(Attachment $attachment) {
    $attachment->setMail($this);
    $this->attachments[] = $attachment;
    return $this;
}

public function removeAppendAttachment(Attachment $attachment) {
    return $this;
}