在Gridview函数yii2中访问变量(Access variable in Gridview function yii2)

 我想访问一个变量的视图文件到Gridview但它抛出的错误， it should be array but null given我宣布$totalDays在我的视图文件的顶部，我在下面的$totalDays使用它 
 
[
            'attribute' =>  'class_id',
            'format' => 'raw',
            'label' => "Class Date",
            'value' => function ($model) {
                array_push($totalDays,$model->class->date);
                return $model->class->date;
            },
            'footer'=> '<span>Total Days</span>',
],
 
 但它会抛出以下错误 
 
 
 
 array_push（）期望参数1是数组，给出null 
 

I am trying to access a variable on view file into Gridview but it is throwing error that it should be array but null given i am declaring $totalDays on top of my view file and i am using it in Gridview like below
 
[
            'attribute' =>  'class_id',
            'format' => 'raw',
            'label' => "Class Date",
            'value' => function ($model) {
                array_push($totalDays,$model->class->date);
                return $model->class->date;
            },
            'footer'=> '<span>Total Days</span>',
],
 
But it throws following error
 
 
 
array_push() expects parameter 1 to be array, null given
 

原文：https://stackoverflow.com/questions/34444766