symfony-2.1 - 表格 : Avoid setting null to non submitted field

Question

我有一个简单的模型(源代码的简化):

class Collection
{
    public $page;
    public $limit;
}

和一个表单类型:

class CollectionType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('page', 'integer');
        $builder->add('limit', 'integer');
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'FSC\Common\Rest\Form\Model\Collection',
        ));
    }
}

我的 Controller :

public function getUsersAction(Request $request)
{
    $collection = new Collection();
    $collection->page = 1;
    $collection->limit = 10;

    $form = $this->createForm(new CollectionType(), $collection)
    $form->bind($request);

    print_r($collection);exit;
}

当我 POST /users/?form[page]=2&form[limit]=20 ， react 是我所期望的:

Collection Object
(
    [page:public] => 2
    [limit:public] => 20
)

现在，当我 POST /users/?form[page]=3 ，响应为:

Collection Object
(
    [page:public] => 3
    [limit:public] =>
)

limit变为 null，因为它没有被提交。

我想得到

Collection Object
(
    [page:public] => 3
    [limit:public] => 10 // The default value, set before the bind
)

问题 :如何更改表单行为，使其忽略未提交的值？

Answer 1

如果只是参数(GET参数)的问题，您可以将默认值定义到路由文件中

route_name:
pattern: /users/?form[page]={page}&form[limit]={limit}
defaults: { _controller: CompanyNameBundleName:ControllerName:ActionName, 
                         limit:10 }

另一种方法是使用 Hook (即 PRE_BIND )并将该值手动更新到此事件中。这样，您就没有将“逻辑”传播到多段代码中。

最终代码 - 由 Adrien 建议 - 将是

<?php

use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormFactoryInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Form\FormEvents;

class IgnoreNonSubmittedFieldSubscriber implements EventSubscriberInterface
{
    private $factory;

    public function __construct(FormFactoryInterface $factory)
    {
        $this->factory = $factory;
    }

    public static function getSubscribedEvents()
    {
        return array(FormEvents::PRE_BIND => 'preBind');
    }

    public function preBind(FormEvent $event)
    {
        $submittedData = $event->getData();
        $form = $event->getForm();

        // We remove every child that has no data to bind, to avoid "overriding" the form default data
        foreach ($form->all() as $name => $child) {
            if (!isset($submittedData[$name])) {
                $form->remove($name);
            }
        }
    }
}