use_virtuals_forms.rst

.. index::
   single: Form; Virtual forms

How to use the Virtual Form Field Option

The virtual form field option can be very useful when you have some duplicated fields in different entities.

For example, imagine you have two entities, a Company and a Customer:

// src/Acme/HelloBundle/Entity/Company.php
namespace Acme\HelloBundle\Entity;

class Company
{
    private $name;
    private $website;

    private $address;
    private $zipcode;
    private $city;
    private $country;
}

// src/Acme/HelloBundle/Entity/Company.php
namespace Acme\HelloBundle\Entity;

class Customer
{
    private $firstName;
    private $lastName;

    private $address;
    private $zipcode;
    private $city;
    private $country;
}

Like you can see, each entity shares a few of the same fields: address, zipcode, city, country.

Now, you want to build two forms: one for a Company and the second for a Customer.

Start by creating a very simple CompanyType and CustomerType:

// src/Acme/HelloBundle/Form/Type/CompanyType.php
namespace Acme\HelloBundle\Form\Type;

use Symfony\Component\Form\FormBuilderInterface;

class CompanyType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('name', 'text')
            ->add('website', 'text')
        ;
    }
}

// src/Acme/HelloBundle/Form/Type/CustomerType.php
namespace Acme\HelloBundle\Form\Type;

use Symfony\Component\Form\FormBuilderInterface;

class CustomerType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('firstName', 'text')
            ->add('lastName', 'text')
        ;
    }
}

Now, we have to deal with the four duplicated fields. Here is a (simple) location form type:

// src/Acme/HelloBundle/Form/Type/LocationType.php
namespace Acme\HelloBundle\Form\Type;

use Symfony\Component\Form\FormBuilderInterface;

class LocationType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('address', 'textarea')
            ->add('zipcode', 'text')
            ->add('city', 'text')
            ->add('country', 'text')
        ;
    }

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

We don't actually have a location field in each of our entities, so we can't directly link our LocationType to our CompanyType or CustomerType. But we absolutely want to have a dedicated form type to deal with location (remember, DRY!).

The virtual form field option is the solution.

We can set the option 'virtual' => true in the getDefaultOptions method of LocationType and directly start using it in the two original form types.

Look at the result:

// CompanyType
public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('foo', new LocationType());
}

// CustomerType
public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('bar', new LocationType());
}

With the virtual option set to false (default behavior), the Form Component expect each underlying object to have a foo (or bar) property that is either some object or array which contains the four location fields. Of course, we don't have this object/array in our entities and we don't want it!

With the virtual option set to true, the Form component skips the foo (or bar) property, and instead "gets" and "sets" the 4 location fields directly on the underlying object!

Note

Instead of setting the virtual option inside LocationType, you can (just like with any options) also pass it in as an array option to the third argument of $builder->add().