public function actionIndex()
    {
        $searchModel = new MahasiswaSearch();
        $dataProvider = $searchModel->search(Yii::$app->request->queryParams);
        
        $field = [
            'fileImport' => 'File Import',
        ];
        $modelImport = DynamicModel::validateData($field, [
            [['fileImport'], 'required'],
            [['fileImport'], 'file', 'extensions'=>'xls,xlsx','maxSize'=>1024*1024],
        ]);
        
        return $this->render('index', [
            'searchModel' => $searchModel,
            'dataProvider' => $dataProvider,
            'modelImport' => $modelImport,
        ]);
    }