Validating dynamically loaded choices in Symfony 2

Question

I have a choice field type named *sub_choice* in my form whose choices will be dynamically loaded through AJAX depending on the selected value of the parent choice field, na

Answer 1

you cannot not build the sub_choice validation because during you config its validator you don't know which values are valid (values depend on value of parent_choice).

What you can do is to resolve parent_choice into entity before you make new YourFormType() in your controller. Then you can get all the possible values for sub_choice and provide them over the form constructor - new YourFormType($subChoice).

In YourFormType you have to add __construct method like this one:

/**
 * @var array
 */
protected $subChoice = array();

public function __construct(array $subChoice)
{
    $this->subChoice = $subChoice;
}

and use provided values in form add:

$builder->add('sub_choice', 'choice', array(
                'label' => 'Sub Choice',
                'choices' => $this->subChoice,
                'virtual' => true
));