[FEATURE] Make it possible to assign variables to view

In event FormControllerFormActionEvent, make it possible to assign
variables to view.

Resolves: in2code-de#1198

Classes/Controller/FormController.php

@@ -78,7 +78,7 @@ public function formAction(): ResponseInterface
 
         /** @var FormControllerFormActionEvent $event */
         $event = $this->eventDispatcher->dispatch(
-            GeneralUtility::makeInstance(FormControllerFormActionEvent::class, $form, $this)
+            GeneralUtility::makeInstance(FormControllerFormActionEvent::class, $form, $this, $this->view)
         );
         $form = $event->getForm();
         SessionUtility::saveFormStartInSession($this->settings, $form);

Classes/Events/FormControllerFormActionEvent.php

@@ -5,6 +5,7 @@
 
 use In2code\Powermail\Controller\FormController;
 use In2code\Powermail\Domain\Model\Form;
+use TYPO3Fluid\Fluid\View\ViewInterface;
 
 final class FormControllerFormActionEvent
 {
@@ -18,14 +19,17 @@ final class FormControllerFormActionEvent
      */
     protected FormController $formController;
 
+    protected ViewInterface $view;
+
     /**
      * @param Form|null $form
      * @param FormController $formController
      */
-    public function __construct(?Form $form, FormController $formController)
+    public function __construct(?Form $form, FormController $formController, ViewInterface $view)
     {
         $this->form = $form;
         $this->formController = $formController;
+        $this->view = $view;
     }
 
     /**
@@ -53,4 +57,28 @@ public function getFormController(): FormController
     {
         return $this->formController;
     }
+
+    /**
+     * Add a variable to the view data collection.
+     * Can be chained, so $this->view->assign(..., ...)->assign(..., ...); is possible
+     *
+     * @param string $key Key of variable
+     * @param mixed $value Value of object
+     * @return ViewInterface an instance of $this, to enable chaining
+     */
+    public function assign(string $key, mixed $value)
+    {
+        $this->view->assign($key, $value)
+    }
+
+    /**
+     * Add multiple variables to the view data collection
+     *
+     * @param array $values array in the format array(key1 => value1, key2 => value2)
+     * @return ViewInterface an instance of $this, to enable chaining
+     */
+    public function assignMultiple(array $values)
+    {
+        $this->view->assignMultiple($values);
+    }
 }