public function excel($params)
 {
     $query = RceExamenExamen::find();
     $dataProvider = new ActiveDataProvider(['query' => $query, 'pagination' => array('pageSize' => 10000)]);
     $this->load($params);
     if (!$this->validate()) {
         // uncomment the following line if you do not want to return any records when validation fails
         // $query->where('0=1');
         return $dataProvider;
     }
     $query->andFilterWhere(['id' => $this->id, 'rce_examen_id' => $this->rce_examen_id, 'examen_id' => $this->examen_id, 'monto_a_pagar' => $this->monto_a_pagar]);
     return $dataProvider;
 }