<?= GridView::widget([        'dataProvider' => $dataProvider,        //'filterModel' => $searchModel,        'columns' => [            ['class' => 'yiigridSerialColumn'],            //显示的字段            //code的值            ['attribute'=>'这是测试code','value'=>function(){return 'abc';}],            'name',            'population',                        ['class' => 'yiigridActionColumn','header' => '操作',],            [                'label'=>'更多操作',                'format'=>'raw',                'value' => function($data){                    $url = "http://www.baidu.com";                    return Html::a('添加权限组', $url, ['title' => '审核']);                 }            ]                ],    ]); ?>