表单:避免为未提交的字段设置 null [英] Form: Avoid setting null to non submitted field

问题描述

我有一个简单的模型(源代码的简化):

I've got a simple model (simplified of source):

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

还有一个表单类型:

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',
        ));
    }
}

我的控制器:

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 时，响应是我所期望的:

When i POST /users/?form[page]=2&form[limit]=20, the response is what i expect:

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

现在，当我POST/users/?form[page]=3时，响应是:

Now, when i POST /users/?form[page]=3, the response is:

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

limit 变为 null，因为它没有提交.

limit becomes null, because it was not submitted.

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?

Question: How can i change the form behaviour, so that it ignores non submitted values ?

推荐答案

如果只是参数(GET参数)的问题可以在路由文件中定义默认值

If is only a problem of parameters (GET parameters) you can define the default value into routing file

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

另一种方法是使用钩子(即PRE_BINDa>) 并手动将该值更新到此事件中.这样，您就不会将逻辑"分散到多段代码中.

An alternative way could be to use a hook (i.e. PRE_BIND) and update manually that value into this event. In that way you haven't the "logic" spreaded into multi pieces of code.

最终代码 - 由 Adrien 建议 - 将是

Final code - suggested by Adrien - will be

<?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);
            }
        }
    }
}

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