class FormElement

Pre-processes variables for the "form_element" theme hook.

Plugin annotation



Expanded class hierarchy of FormElement

Related topics


class FormElement extends PreprocessBase implements PreprocessInterface {

   * {@inheritdoc}
  public function preprocessElement(Element $element, Variables $variables) {
    // Set has_error flag.
    $variables['has_error'] = $element->getProperty('has_error');

    if ($element->getProperty('autocomplete_route_name')) {
      $variables['is_autocomplete'] = TRUE;

    // See
    $checkbox = $variables['is_checkbox'] = $element->isType('checkbox');
    $radio = $variables['is_radio'] = $element->isType('radio');

    // Determine if the form element should have the "form-group" class added.
    // Use an explicitly set property from the element or use its other
    // properties as the criteria to determine if it should be set.
    $variables['is_form_group'] = $element->getProperty('form_group', !$checkbox && !$radio && !$element->isType('hidden'));

    // Add label_display and label variables to template.
    $display = $variables['label_display'] = $variables['title_display'] = $element->getProperty('title_display');

    // Place single checkboxes and radios in the label field.
    if (($checkbox || $radio)) {
      $label = Element::create($variables['label']);
      $children = &$label->getProperty('children', '');
      $children .= $variables['children'];
      if ($label->getProperty('title_display') != 'none') {

      // Inform label if it is in checkbox/radio context.
      $label->setProperty('is_checkbox', $checkbox);
      $label->setProperty('is_radio', $radio);

      // Pass the label attributes to the label, if available.
      if ($element->hasProperty('label_attributes')) {

    // Remove the #field_prefix and #field_suffix values set in
    // template_preprocess_form_element(). These are handled at the input level.
    // @see \Drupal\bootstrap\Plugin\Preprocess\Input::preprocess().



Contains filters are case sensitive
Name Modifiers Type Description
FormElement::preprocessElement public function Preprocess the variables array if an element is present. Overrides PreprocessBase::preprocessElement
PluginBase::$theme protected property The currently set theme object.
PluginBase::__construct public function
PreprocessBase::$hook protected property The theme hook invoked.
PreprocessBase::$info protected property The theme hook info array from the theme registry.
PreprocessBase::$variables protected property The Variables object.
PreprocessBase::preprocess public function Preprocess theme hook variables. Overrides PreprocessInterface::preprocess
PreprocessBase::preprocessAttributes protected function Ensures all attributes have been converted to an Attribute object.
PreprocessBase::preprocessDescription protected function Converts any set description variable into a traversable array.
PreprocessBase::preprocessVariables protected function Preprocess the variables array.