How can I change form action link?

Question

How can I change form action in drupal 8?

In default, page not change and when my form path is /site/drupal/page, my form action is <form data-drupal-selector="test" action="/site/drupal/page" method="post" id="test" accept-charset="UTF-8">.

But I want change it to other page. How can I do this ?

** Redirect not worked, see this link: Redirect after submit form

Answer 1

In the form submit handler, you can modify the $form['action'] value.

// Get the routename
$routename = 'My-Route';
  $url = \Drupal\Core\Url::fromRoute($routename);
  // make the redirection
  $form['#action'] = $url->toString();

Answer 2

in the submit form write a redirect

use Drupal\Core\Url;
use Symfony\Component\HttpFoundation\RedirectResponse;

//add the below in submit form handler. Use the route name you want to redirect
$response = new RedirectResponse(Url::fromRoute('<front>')->toString());

$response->send();