未定义的变量：karik gridview中的gridColumns：yii2(Undefined variable: gridColumns in karik gridview:yii2)

 我正在尝试使用kartik gridview并得到以下错误。 - 
 
Undefined variable: gridColumns
 
 我已经检查了 - Yii2：Kartik Gridview页脚的总和 。 但是在我的代码中没有找到问题。 
 
 index.php代码 - 
 
<?= GridView::widget([
        'dataProvider' => $dataProvider,
        'filterModel' => $searchModel,
        'columns' => $gridColumns,
        'showPageSummary' => true,
        'columns' => [
            ['class' => 'kartik\grid\SerialColumn'],
            [
                'attribute'=>'s_period',
                'filter'=>ArrayHelper::map(Salary::find()->asArray()->all(), 's_period', 's_period'),
            ],
            's_empid',
            's_empname',
            [
                'attribute'=>'s_epf',
                'pageSummary'=>true
            ],


            //['class' => 'yii\grid\ActionColumn'],
        ],
    ]); ?>

I'm trying to use kartik gridview and got the following error. -
 
Undefined variable: gridColumns
 
I've checked - Yii2: Kartik Gridview sum of a column in footer. But didn't find the issue in my code.
 
Code of index.php - 
 
<?= GridView::widget([
        'dataProvider' => $dataProvider,
        'filterModel' => $searchModel,
        'columns' => $gridColumns,
        'showPageSummary' => true,
        'columns' => [
            ['class' => 'kartik\grid\SerialColumn'],
            [
                'attribute'=>'s_period',
                'filter'=>ArrayHelper::map(Salary::find()->asArray()->all(), 's_period', 's_period'),
            ],
            's_empid',
            's_empname',
            [
                'attribute'=>'s_epf',
                'pageSummary'=>true
            ],


            //['class' => 'yii\grid\ActionColumn'],
        ],
    ]); ?>

原文：https://stackoverflow.com/questions/38289576