/**
* {@inheritdoc}
*/
public function submitForm(array &$form, FormStateInterface $form_state)
{
$name = $form_state->getValue('machine_name');
$type = $form_state->getValue('type');
if ($type === static::NO_CONTEXT_KEY) {
$this->page->removeParameter($name);
$label = NULL;
} else {
$label = $form_state->getValue('label');
$this->page->setParameter($name, $type, $label);
}
$this->page->save();
// Set the submission message.
drupal_set_message($this->t('The %label parameter has been updated.', ['%label' => $label ?: $name]));
$form_state->setRedirectUrl($this->page->toUrl('edit-form'));
}