Using entity form display modes

Question

I have created a custom form display mode my_mode for nodes and wish to display node form using this mode instead of default one at a custom page. How can I do it?

$this->entityFormBuilder()->getForm() accepts an operation as a parameter, but not form mode.

Answer 1

Form modes and form operations are a bit strange. You also need to define a form operation through hook_entity_type_alter() to be able to use a custom form mode.

Which makes the UI to create form modes pretty useless, but ssshh, don't tell anyone :)

For an example, see views_ui_entity_type_build(): $entity_type->setFormClass($operation, $class_name)

Answer 2

Indeed it is quite strange I find to have both operation and form display, but you do not especially need to have a form operation to use your display. You have to use hook_entity_type_alter though...

Here is the way for example to load the "super" form mode (if exists and is activated) :

/**
 * Implements hook_entity_form_display_alter().
 */
function my_module_entity_form_display_alter(&$form_display, $context) {

  // Load the right entity form display.
  $id = $context['entity_type'] . '.' . $context['bundle'] . '.super';
  $storage = \Drupal::entityManager()->getStorage('entity_form_display');
  $change_display = $storage->load($id);

  // If form mode is activated, replace the given one with ours.
  if ($change_display) {
    $form_display = $change_display;
  }
}