表单

Forms are one of the most misused Symfony components due to its vast scope and endless list of features. In this chapter we’ll show you some of the best practices so you can leverage forms but get work done quickly.

定义Forms

最佳实践

Define your forms as PHP classes.

The Form component allows you to build forms right inside your controller code. This is perfectly fine if you don’t need to reuse the form somewhere else. But for organization and reuse, we recommend that you define each form in its own PHP class:

namespace AppBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class PostType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('title')
            ->add('summary', 'textarea')
            ->add('content', 'textarea')
            ->add('authorEmail', 'email')
            ->add('publishedAt', 'datetime')
        ;
    }

    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle\Entity\Post'
        ));
    }

    public function getName()
    {
        return 'post';
    }
}

To use the class, use createForm and instantiate the new class:

use AppBundle\Form\PostType;
// ...

public function newAction(Request $request)
{
    $post = new Post();
    $form = $this->createForm(new PostType(), $post);

    // ...
}

把表单注册为Services

You can also register your form type as a service. But this is not recommended unless you plan to reuse the new form type in many places or embed it in other forms directly or via the collection type.

For most forms that are used only to edit or create something, registering the form as a service is over-kill, and makes it more difficult to figure out exactly which form class is being used in a controller.

表单按钮的配置

Form classes should try to be agnostic to where they will be used. This makes them easier to re-use later.

最佳实践

Add buttons in the templates, not in the form classes or the controllers.

Since Symfony 2.5, you can add buttons as fields on your form. This is a nice way to simplify the template that renders your form. But if you add the buttons directly in your form class, this would effectively limit the scope of that form:

class PostType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            // ...
            ->add('save', 'submit', array('label' => 'Create Post'))
        ;
    }

    // ...
}

This form may have been designed for creating posts, but if you wanted to reuse it for editing posts, the button label would be wrong. Instead, some developers configure form buttons in the controller:

namespace AppBundle\Controller\Admin;

use Symfony\Component\HttpFoundation\Request;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use AppBundle\Entity\Post;
use AppBundle\Form\PostType;

class PostController extends Controller
{
    // ...

    public function newAction(Request $request)
    {
        $post = new Post();
        $form = $this->createForm(new PostType(), $post);
        $form->add('submit', 'submit', array(
            'label' => 'Create',
            'attr'  => array('class' => 'btn btn-default pull-right')
        ));

        // ...
    }
}

This is also an important error, because you are mixing presentation markup (labels, CSS classes, etc.) with pure PHP code. Separation of concerns is always a good practice to follow, so put all the view-related things in the view layer:

{{ form_start(form) }}
    {{ form_widget(form) }}

    <input type="submit" value="Create"
           class="btn btn-default pull-right" />
{{ form_end(form) }}

输出表单HTML

There are a lot of ways to render your form, ranging from rendering the entire thing in one line to rendering each part of each field independently. The best way depends on how much customization you need.

One of the simplest ways - which is especially useful during development - is to render the form tags and use form_widget() to render all of the fields:

{{ form_start(form, {'attr': {'class': 'my-form-class'} }) }}
    {{ form_widget(form) }}
{{ form_end(form) }}

If you need more control over how your fields are rendered, then you should remove the form_widget(form) function and render your fields individually. See the How to Customize Form Rendering article for more information on this and how you can control how the form renders at a global level using form theming.

处理表单提交

Handling a form submit usually follows a similar template:

public function newAction(Request $request)
{
    // build the form ...

    $form->handleRequest($request);

    if ($form->isSubmitted() && $form->isValid()) {
        $em = $this->getDoctrine()->getManager();
        $em->persist($post);
        $em->flush();

        return $this->redirect($this->generateUrl(
            'admin_post_show',
            array('id' => $post->getId())
        ));
    }

    // render the template
}

There are really only two notable things here. First, we recommend that you use a single action for both rendering the form and handling the form submit. For example, you could have a newAction that only renders the form and a createAction that only processes the form submit. Both those actions will be almost identical. So it’s much simpler to let newAction handle everything.

Second, we recommend using $form->isSubmitted() in the if statement for clarity. This isn’t technically needed, since isValid() first calls isSubmitted(). But without this, the flow doesn’t read well as it looks like the form is always processed (even on the GET request).

Custom Form Field Types

最佳实践

Add the app_ prefix to your custom form field types to avoid collisions.

Custom form field types inherit from the AbstractType class, which defines the getName() method to configure the name of that form type. These names must be unique in the application.

If a custom form type uses the same name as any of the Symfony’s built-in form types, it will override it. The same happens when the custom form type matches any of the types defined by the third-party bundles installed in your application.

Add the app_ prefix to your custom form field types to avoid name collisions that can lead to hard to debug errors.