Views

Include HTML

<?= \Yii::$app->view->renderFile('@app/views/site/fileToInclude.php'); ?>

Set Flash

Terugkoppeling vanuit de controller naar de view.

In Controller

Yii::$app->session->setFlash('success', "Exam deleted.");

of

Yii::$app->session->setFlash('error', "Exam cannot be deleten, it has still forms attached to it.");

In View

  <?php if (Yii::$app->session->hasFlash('success')): ?>
    <div class="alert alert-success alert-dismissable">
         <button aria-hidden="true" data-dismiss="alert" class="close" type="button">×</button>
         <?= Yii::$app->session->getFlash('success') ?>
    </div>
  <?php endif; ?>

  <?php if (Yii::$app->session->hasFlash('error')): ?>
    <div class="alert alert-danger alert-dismissable">
      <button aria-hidden="true" data-dismiss="alert" class="close" type="button">×</button>
      <?= Yii::$app->session->getFlash('error') ?>
    </div>
  <?php endif; ?> 

Redirect

return $this->redirect(['index']);