I am trying to create a simple form with a single field. I have a custom constraint created for the validation of a custom field.
I would like to add the same constraint to the form element, instead of duplicating the code from the constraint class in the form validation handler.
namespace Drupal\mymodule\Form;
use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
/**
* Provides a My Module form.
*/
class ExampleForm extends FormBase {
/**
* {@inheritdoc}
*/
public function getFormId() {
return 'mymodule_example';
}
/**
* {@inheritdoc}
*/
public function buildForm(array $form, FormStateInterface $form_state) {
$form['message'] = [
'#type' => 'textarea',
'#title' => $this->t('Message'),
'#required' => TRUE,
];
$form['actions'] = [
'#type' => 'actions',
];
$form['actions']['submit'] = [
'#type' => 'submit',
'#value' => $this->t('Send'),
];
return $form;
}
/**
* {@inheritdoc}
*/
public function validateForm(array &$form, FormStateInterface $form_state) {
// Check for the possibility if ->addConstraint() can be used here
if (mb_strlen($form_state->getValue('message')) < 10) {
$form_state->setErrorByName('name', $this->t('Message should be at least 10 characters.'));
}
}
/**
* {@inheritdoc}
*/
public function submitForm(array &$form, FormStateInterface $form_state) {
$this->messenger()->addStatus($this->t('The message has been sent.'));
$form_state->setRedirect('<front>');
}
}
Is it possible?