Symfony3"选项"占位符"不存在."

Question

我想创建一个用户设置面板.

在表单中,我希望有一个占位符,其中包含用户对其参数的当前值.

这是一个示例代码:

//...

$form = $this->createFormBuilder($user)
            ->add('Username', TextType::class, array(
                'label' => "Change UserName",
                'placeholder' => $userData[0]->getUsername()
            ))
//...

使用这些值我在浏览器中收到此错误:

选项"占位符"不存在.定义的选项包括:"action","allow_extra_fields","attr","auto_initialize","block_name","by_reference","compound","constraints","csrf_field_name","csrf_message","csrf_protection","csrf_token_id ","csrf_token_manager","data","data_class","disabled","empty_data","error_bubbling","error_mapping","extra_fields_message","inherit_data","invalid_message","invalid_message_parameters","label", "label_attr","label_format","mapped","method","post_max_size_message","property_path","required","translation_domain","trim","upload_max_size_message","validation_groups".

问题仅在于参数本身,因为'data' => $userData[0]->getUsername()工作并显示正确的信息.

以下是我的页面的使用参数:

namespace AppBundle\Controller;

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use AppBundle\Entity\Task;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\Form\Extension\Core\Type\TextareaType;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use AppBundle\Entity\Post;
use AppBundle\Entity\User; 

Answer 1

placeholder 是一个html属性.

$form = $this->createFormBuilder($user)
        ->add('Username', TextType::class, array(
            'label' => "Change UserName",
            'attr' => array(
                'placeholder' => $userData[0]->getUsername()
                )
            )
        )