public function actionChangeState()
 {
     $request = Yii::$app->request;
     if ($request->isAjax) {
         $newState = $request->post('newState');
         $examTemplateId = intval($request->post('id'));
         if ($newState == 'open') {
             $newState = ExamTemplate::STATE_ABLE;
             ExamTemplate::updateState($examTemplateId, $newState);
             return 'open';
         } elseif ($newState == 'close') {
             $newState = ExamTemplate::STATE_DISABLE;
             ExamTemplate::updateState($examTemplateId, $newState);
             return 'close';
         } else {
             return '状态非法';
         }
     } else {
         throw new Exception('非ajax提交');
     }
 }