调用控制器动作在另一个控制器，制作小部件

I have a problem in Yii framework, I want to call a controller's action in the layout/main.php page which is belong to the siteController, I did this:

$a = UsersController::actionRequestAlert($s);

then I got this error:

Non-static method UsersController::actionRequestAlert() should not be called statically, assuming $this from incompatible context

so how can I solve this problem?

ok, now I want to create a widget, here is the steps I made:

• created folder 'widgets' in folder 'protected'.
• created folder 'views' in folder 'widgets'.
• added this in config/main.php : 'application.widgets.*'

• this is the code of widgets/Alert.php :

  class AlertWidget extends CWidget { public $alert = null;

  private $_data = null;
  
  public function init()
  {
      $s = Yii::app()->session['userId'];
      $r = Requests::model()->findAll('idUser='.$s.' and confirm =0 and unconfirm=0 and cancel=0');
      $i=0;
      foreach($r as $x)
          $i++;
          if($i<=0)
              $alert=null;
          else
              $alert="(".$i.")";
      $this->_data = new CActiveDataProvider($alert);
  }
  
  public function run()
  {
      $this->render('alert', ['data' => $this->_data]);
  }
  

  }

• this is the code of widgets/views/alert.php:

  echo $data;

• this is the code to how I use the widget in a view:

  $this->widget('application.widgets.Alert');

finally I got these errors:

( ! ) SCREAM: Error suppression ignored for
( ! ) Fatal error: Cannot redeclare class AlertWidget in C:\wamp\www\mediastore\protected\widgets\Alert.php on line 27

About first question: You must define method actionRequestAlert() as static

public static actionRequestAlert() {}