Controller:
public function actionSearch()
    {
        $user_search = new UserSearch(Yii::$app->request->queryParams);  //问题所在
        return $data['items'] = $user_search->Search(Yii::$app->request->queryParams);
    }

ModelSearch:

    public function search($params)
    {
        $query = User::find();

        // add conditions that should always apply here

        $dataProvider = new ActiveDataProvider([
            'query' => $query,
        ]);

        $this->load($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;
        }
        // grid filtering conditions
        $query->andFilterWhere([
            'id' => $this->id,
            'birth' => $this->birth,
        ]);

        $query->andFilterWhere(['like', 'name', $this->name])
            ->andFilterWhere(['like', 'sex', $this->sex]);

        return $dataProvider;
    }

问题表现 : $user_search = new UserSearch(Yii::$app->request->queryParams); 实例化这个类时不传参数会报错 ,传参数才能根据过滤条件返回数据