DataTransformer但不存在这样的服务

Question

使用Symfony 5，我有一个非常简单的DataTransformer：

namespace App\Form\DataTransformer;

use Symfony\Component\DependencyInjection\ParameterBag\ParameterBagInterface;
use Symfony\Component\Form\DataTransformerInterface;

class UploadTransformer implements DataTransformerInterface
{
    private $uploadDirectory;

    public function __construct(ParameterBagInterface $parameters)
    {
        $this->uploadDirectory = $parameters->get('upload_directory');
    }

    ...

我还创建了一种表格类型：

namespace App\Form\Type;

use App\Form\DataTransformer\UploadTransformer;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\HiddenType;
use Symfony\Component\Form\FormBuilderInterface;

class UploadType extends AbstractType
{
    private $uploadTransformer;

    public function __construct(UploadTransformer $uploadTransformer)
    {
        $this->uploadTransformer = $uploadTransformer;
    }

    ...

但是此表格返回错误：

无法自动装配服务“ App \ Form \ Type \ UploadType”：方法“ __construct（）”的参数“ $ uploadTransformer”引用类“ App \ Form \ DataTransformer \ UploadTransformer”，但不存在此类服务。

我不明白此错误，因为：

• 当我不注入DataTransformer时，表单运行良好；
• [我想我完全按照Symfony文档的要求创建了一个变形器：https://symfony.com/doc/current/form/data_transformers.html#using-the-transformer

我知道我可以从services.yaml注入服务，但是通常不应该自动注入DataTransformer，如文档中所示吗？

我的services.yaml：

services:
    _defaults:
        autowire: true      # Automatically injects dependencies in your services.
        autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.

    App\:
        resource: '../src/*'
        exclude: '../src/{DependencyInjection,Entity,Migrations,Tests,Kernel.php}'

    App\Controller\:
        resource: '../src/Controller'
        tags: ['controller.service_arguments']

Answer 1

我认为您的services.yaml中缺少此内容>

services:
    # default configuration for services in *this* file
    _defaults:
        autowire: true      # Automatically injects dependencies in your services.