如何创建一个自定义的SaveType，它是Symfony表单中SubmitType的子级

我想在Symfony中制作一些简单的管理面板应用程序。我看到自 2.3 版以来，Symfony 引入了 Bootstrap 的表单主题，这很棒，但我想创建名为 SaveType 的自定义提交字段，该字段应将默认类 attr 设置为 btn-primary 而不是 btn-default。

因此，从文档中我读到我可以创建该自定义字段类型并将其父字段设置为SubmitType

保存类型自定义域

<?php
namespace AppBundle'Form'Custom;
use Symfony'Component'Form'AbstractType;
use Symfony'Component'Form'Extension'Core'Type'SubmitType;
use Symfony'Component'OptionsResolver'OptionsResolver;
/**
 * Class SaveType
 * @package AppBundle'Form
 */
class SaveType extends AbstractType
{
    /**
     * @param OptionsResolver $resolver
     * @return OptionsResolver|void
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        return $resolver->setDefaults(
            [
                'attr' => [
                    'class' => 'btn-primary',
                ],
            ]
        );
    }
    /**
     * @return string
     */
    public function getParent()
    {
        return SubmitType::class;
    }
}

产品实体

<?php
namespace AppBundle'Entity;
/**
 * Product
 */
class Product
{
    /**
     * @var int
     */
    private $id;
    /**
     * @var string
     */
    private $name;
    /**
     * @var int
     */
    private $price;
    /**
     * @var bool
     */
    private $enabled;

    /**
     * Get id
     *
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }
    /**
     * Set name
     *
     * @param string $name
     *
     * @return Product
     */
    public function setName($name)
    {
        $this->name = $name;
        return $this;
    }
    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }
    /**
     * Set price
     *
     * @param integer $price
     *
     * @return Product
     */
    public function setPrice($price)
    {
        $this->price = $price;
        return $this;
    }
    /**
     * Get price
     *
     * @return int
     */
    public function getPrice()
    {
        return $this->price;
    }
    /**
     * Set enabled
     *
     * @param boolean $enabled
     *
     * @return Product
     */
    public function setEnabled($enabled)
    {
        $this->enabled = $enabled;
        return $this;
    }
    /**
     * Get enabled
     *
     * @return bool
     */
    public function getEnabled()
    {
        return $this->enabled;
    }
}

使用保存类型的产品类型

<?php
namespace AppBundle'Form;
use AppBundle'Form'Custom'SaveType;
use Symfony'Component'Form'AbstractType;
use Symfony'Component'Form'Extension'Core'Type'MoneyType;
use Symfony'Component'Form'FormBuilderInterface;
use Symfony'Component'OptionsResolver'OptionsResolver;
/**
 * Class ProductType
 * @package AppBundle'Form
 */
class ProductType extends AbstractType
{
    /**
     * @param FormBuilderInterface $builder
     * @param array                $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('name')
            ->add('price', MoneyType::class, [
                'currency' => 'PLN',
                'divisor' => 100,
            ])
            ->add('enabled')
            ->add('submit', SaveType::class, [
                'label' => 'Save',
            ]);
    }
    /**
     * @param OptionsResolver $resolver
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle'Entity'Product',
        ));
    }
}

问题所在

呈现该表单会引发以下错误：

Neither the property "submit" nor one of the methods "getSubmit()", "submit()", "isSubmit()", "hasSubmit()", "__get()" exist and have public access in class "AppBundle'Entity'Product".

注意

创建 SubmitTypeExtension 工作正常，但我不想更改整个应用程序中标准 SubmitType 的行为。