Symfony 7.4 Form Component

GitHub: https://github.com/symfony/form Docs: https://symfony.com/doc/7.4/components/form.html

Quick Reference

Creating a Form Type

php

namespace App\Form;

use App\Entity\Task;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\DateType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class TaskType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options): void
    {
        $builder
            ->add('task', TextType::class)
            ->add('dueDate', DateType::class);
    }

    public function configureOptions(OptionsResolver $resolver): void
    {
        $resolver->setDefaults([
            'data_class' => Task::class,
        ]);
    }
}

Handling Submission in Controller

php

public function new(Request $request): Response
{
    $task = new Task();
    $form = $this->createForm(TaskType::class, $task);
    $form->handleRequest($request);

    if ($form->isSubmitted() && $form->isValid()) {
        // persist $task ...
        return $this->redirectToRoute('task_success');
    }

    return $this->render('task/new.html.twig', ['form' => $form]);
}

Adding Validation Constraints

php

use Symfony\Component\Validator\Constraints as Assert;

$builder->add('task', TextType::class, [
    'constraints' => [new Assert\NotBlank(), new Assert\Length(['min' => 3])],
]);

Form Events (Dynamic Fields)

php

use Symfony\Component\Form\FormEvents;
use Symfony\Component\Form\FormEvent;

$builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event): void {
    $data = $event->getData();
    $form = $event->getForm();
    if (!$data || null === $data->getId()) {
        $form->add('name', TextType::class);
    }
});

Data Transformer (Model Transformer)

php

use Symfony\Component\Form\CallbackTransformer;

$builder->get('tags')
    ->addModelTransformer(new CallbackTransformer(
        fn (?array $tags): string => implode(', ', $tags ?? []),
        fn (string $tags): array => explode(', ', $tags),
    ));

Rendering in Twig

twig

{{ form_start(form) }}
    {{ form_row(form.task) }}
    {{ form_row(form.dueDate) }}
    <button type="submit">Save</button>
{{ form_end(form) }}

Unit Testing a Form Type

php

use Symfony\Component\Form\Test\TypeTestCase;

class TaskTypeTest extends TypeTestCase
{
    public function testSubmitValidData(): void
    {
        $formData = ['task' => 'Write tests', 'dueDate' => ['year' => '2026', 'month' => '1', 'day' => '1']];
        $form = $this->factory->create(TaskType::class);
        $form->submit($formData);

        $this->assertTrue($form->isSynchronized());
        $this->assertTrue($form->isValid());
    }
}

Full Documentation

For complete details including all form events, data transformers (model vs view), data mappers, custom form types, form type extensions, dynamic form modification, validation groups, form rendering functions, form themes, and testing patterns, see references/form.md.