如何让Yii2处理数据提供者的两个不同实例？

你需要换dataProvider2到dataProvider

Member
 $dataProvider2,//Error $dataProvider2 not found
    'columns' => [
        ['class' => 'yii\grid\SerialColumn'],
        [

            'attribute'=>'memberCode',
            'format' => 'raw',
            'value'=>function ($model, $index, $widget) {

            },
        ],
        'firstName',
    ]
]); ?>

既然dataProvider是GridView的属性..它会起作用

并将控制器操作更改为

return $this->render('index', [
        'dataProvider' => $dataProvider,'dataProvider2'=>$dataProvider2 ]);