drupal_*_form() and form_*() methods are replaced by a form builder service and methods on $form_state

In Drupal 7 forms have been basically used with drupal_get_form().
In Drupal 8 all the functions like drupal_prepare_form() etc. are replaced with a form builder service.

Drupal 7


$parameter = 'new';
$form = drupal_get_form('comment_admin_overview', $parameter);

return $form;

Drupal 8

$parameter = 'new';
$form = \Drupal::formBuilder()->getForm('Drupal\comment\Form\CommentAdminOverview', $parameter);

Before	After
`drupal_get_form()`	`\Drupal::formBuilder()->getForm()`
`drupal_build_form()`	`\Drupal::formBuilder()->buildForm()`
`form_state_defaults()`	`\Drupal::formBuilder()->getFormStateDefaults()`
`drupal_rebuild_form()`	`\Drupal::formBuilder()->rebuildForm()`
`form_get_cache()`	`\Drupal::formBuilder()->getCache()`
`form_set_cache()`	`\Drupal::formBuilder()->setCache()`
`drupal_validate_form()`	`\Drupal::service('form_validator')->validateForm()`
`drupal_form_submit()`	`\Drupal::formBuilder()->submitForm()`
`drupal_retrieve_form()`	`\Drupal::formBuilder()->retrieveForm()`
`drupal_process_form()`	`\Drupal::formBuilder()->processForm()`
`drupal_prepare_form()`	`\Drupal::formBuilder()->prepareForm()`
`drupal_redirect_form()`	`\Drupal::formBuilder()->redirectForm()`
`form_execute_handlers($type)`, $type either 'submit' or 'validate'	Either `\Drupal::formBuilder()->executeSubmitHandlers()` or `\Drupal::service('form_validator')->executeValidateHandlers()`
`form_set_error()`	`$form_state->setErrorByName()`
`form_clear_error()`	`$form_state->clearErrors()`
`form_get_errors()`	`$form_state->getErrors()`
`form_get_error()`	`$form_state->getError()`
`form_error()`	`$form_state->setError()`
`form_set_value()`	`$form_state->setValueForElement()`
`form_load_include($form_state, $type, $module, $name = NULL)`	`$form_state->loadInclude($module, $type, $name = NULL)`
`form_state_values_clean(&$form_state)`	`$form_state->cleanValues()`

Impacts:

Module developers

Updates Done (doc team, etc.)

Online documentation:

Not done

Theming guide:

Not done

Module developer documentation:

Not done

Examples project:

Not done

Coder Review:

Not done

Coder Upgrade:

Not done

Other:

Other updates done

Comments

Uses class instead of form id.

TwoD

Swedish

Sweden

commented 29 December 2016 at 07:39

The getForm()/buildForm() methods now only accept the name of a class implementing \Drupal\Core\FormInterface as a string, or an actual instance of such a class, instead of the form id. (The id is still used for form alter hooks etc.)