function hook_form_BASE_FORM_ID_alter in Zircon Profile 8
Same name and namespace in other branches
- 8.0 core/lib/Drupal/Core/Form/form.api.php \hook_form_BASE_FORM_ID_alter()
Provide a form-specific alteration for shared ('base') forms.
By default, when \Drupal::formBuilder()->getForm() is called, Drupal looks for a function with the same name as the form ID, and uses that function to build the form. In contrast, base forms allow multiple form IDs to be mapped to a single base (also called 'factory') form function.
Modules can implement hook_form_BASE_FORM_ID_alter() to modify a specific base form, rather than implementing hook_form_alter() and checking for conditions that would identify the shared form constructor.
To identify the base form ID for a particular form (or to determine whether one exists) check the $form_state. The base form ID is stored under $form_state->getBuildInfo()['base_form_id'].
Form alter hooks are called in the following order: hook_form_alter(), hook_form_BASE_FORM_ID_alter(), hook_form_FORM_ID_alter(). See hook_form_alter() for more details.
Parameters
$form: Nested array of form elements that comprise the form.
$form_state: The current state of the form.
$form_id: String representing the name of the form itself. Typically this is the name of the function that generated the form.
See also
\Drupal\Core\Form\FormBuilderInterface::prepareForm()
Related topics
53 functions implement hook_form_BASE_FORM_ID_alter()
Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.
- automated_cron_form_system_cron_settings_alter in core/
modules/ automated_cron/ automated_cron.module - Implements hook_form_FORM_ID_alter() for the system_cron_settings() form.
- block_form_form_test_alter_form_alter in core/
modules/ system/ tests/ modules/ form_test/ form_test.module - Implements hook_form_FORM_ID_alter() on behalf of block.module.
- book_form_node_delete_confirm_alter in core/
modules/ book/ book.module - Implements hook_form_FORM_ID_alter() for node_delete_confirm().
- book_form_node_form_alter in core/
modules/ book/ book.module - Implements hook_form_BASE_FORM_ID_alter() for node_form().
- color_form_system_theme_settings_alter in core/
modules/ color/ color.module - Implements hook_form_FORM_ID_alter().
File
- core/
lib/ Drupal/ Core/ Form/ form.api.php, line 281 - Callbacks and hooks related to form system.
Code
function hook_form_BASE_FORM_ID_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
// Modification for the form with the given BASE_FORM_ID goes here. For
// example, if BASE_FORM_ID is "node_form", this code would run on every
// node form, regardless of node type.
// Add a checkbox to the node form about agreeing to terms of use.
$form['terms_of_use'] = array(
'#type' => 'checkbox',
'#title' => t("I agree with the website's terms and conditions."),
'#required' => TRUE,
);
}