public BookAdminEditForm::validateForm(array &$form, FormStateInterface $form_state)
Form validation handler.
Parameters
array $form: An associative array containing the structure of the form.
\Drupal\Core\Form\FormStateInterface $form_state: The current state of the form.
Overrides FormBase::validateForm
File
- core/modules/book/src/Form/BookAdminEditForm.php, line 84
Class
- BookAdminEditForm
- Provides a form for administering a single book's hierarchy.
Namespace
Drupal\book\Form
Code
public function validateForm(array &$form, FormStateInterface $form_state) {
if ($form_state->getValue('tree_hash') != $form_state->getValue('tree_current_hash')) {
$form_state->setErrorByName('', $this->t('This book has been modified by another user, the changes could not be saved.'));
}
}
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