Provides an interface for form building and processing. Hierarchy interface \Drupal\Core\Form\

public FormBuilderInterface::processForm($form_id, &$form

public FormBuilderInterface::submitForm($form_arg, FormStateInterface

public FormBuilderInterface::buildForm($form_id, FormStateInterface

public FormBuilderInterface::getForm($form_arg)

public FormBuilderInterface::rebuildForm($form_id, FormStateInterface

public FormBuilderInterface::getFormId($form_arg, FormStateInterface

public FormBuilderInterface::retrieveForm($form_id, FormStateInterface

public FormBuilderInterface::prepareForm($form_id, &$form

Request key for AJAX forms that submit to the form's original route. This constant is distinct from a "drupal_ajax" value for