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How to (dynamically) remove a Form Field
How to (dynamically) remove a Form Field¶
From ThiagoKrug:
Hi, I am reusing one form but I have one specific controller action that I need remove one field form, How can I do it without creating new form? Thanks!
Answer¶
Note
Special thanks to our very-own Roman on this answer!
Cool question! There are actually multiple ways to achieve this task, ranging from a very simple ->remove() method call to setting up a form event listener.
Let’s review the two easiest and most common ways.
First, initialize a simple form type with two fields:
// src/KnpU/QADayBundle/Form/Type/RemoveFormFieldType.php
namespace KnpU\QADayBundle\Form\Type;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
class RemoveFormFieldType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('first', 'text')
->add('second', 'text')
;
}
public function getName()
{
return 'remove_form_field';
}
}
Next, let’s build the two different controllers that will render this form to show off the two solutions:
// src/KnpU/QADayBundle/Controller/RemoveFormFieldController.php
namespace KnpU\QADayBundle\Controller;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use KnpU\QADayBundle\Form\Type\RemoveFormFieldType;
class RemoveFormFieldController extends Controller
{
public function firstWayAction()
{
$form = $this->createForm(new RemoveFormFieldType());
// form processing...
return $this->render('QADayBundle:RemoveFormField:form.html.twig', array(
'form' => $form->createView()
));
}
public function secondWayAction()
{
// same as firstWayAction() for now
}
}
Awesome! Now, let’s solve this in 2 different ways.
Option 1: Using remove¶
The most straightforward way to achieve this is by removing the form field you want with the remove function:
public function firstWayAction()
{
$form = $this->createForm(new RemoveFormFieldType());
$form->remove('second');
// form processing...
return $this->render('QADayBundle:RemoveFormField:form.html.twig', array(
'form' => $form->createView()
));
}
And that’s it! No changes to RemoveFormFieldType are required at all! And the best part is that this is a perfectly valid solution, no need to over-think it :).
Option 2: Using Form Options¶
But if you want a more advanced solution with a bit more flexibility, there’s another way!
First, let’s tweak the form type a bit to rely on a custom option passed on initialization:
// src/KnpU/QADayBundle/Controller/RemoveFormFieldController.php
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
// ...
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder->add('first', 'text');
if ($options['use_second']) {
$builder->add('second', 'text');
}
}
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver->setDefaults(array(
'use_second' => true
));
}
Now, when you create the form, pass the option and you’re ready to go!
public function secondWayAction()
{
// the "null" option is the form data - you might pass something here
$form = $this->createForm(new RemoveFormFieldType(), null, array(
'use_second' => false
));
return $this->render('QADayBundle:RemoveFormField:form.html.twig', array(
'form' => $form->createView()
));
}
That’s it! There is also an event dispatching/listening system in the Form component, which allows you to dynamically add/remove/modify fields based on anything (e.g. user-submitted data). For more information, see How to Dynamically Modify Forms Using Form Events.
Have fun!
asd