yii2关系中每个条目的gridview中的单独逗号数据

I have 3 tables and i have made relation to What table by using Field table. i want to show name row from What table in Gridview.but it shows me row of data seperated by comma. i want each data in different column. like sql query result with repeated field.
this is my tbon.php model:

public function getWhat()
    {
        return $this->hasMany(What::className(), ['idw' => 'idw'])
            ->viaTable('Field', ['id' => 'id']);
    }
public function getField()
    {
        return $this->hasMany(Field::className(), ['id' => 'id']);
    }

and in TbonSearch.php i have added these codes:

public $what;
public $field;

and

[['field','what'],'safe']

and in search method, i have added:

$query = Tbon::find()
           ->joinWith(['field'])
           ->joinWith(['what']);

and for sorting:

$dataProvider->sort->attributes['what'] = [
            'asc' => ['what.name' => SORT_ASC],
            'desc' => ['what.name' => SORT_DESC],

        ]; 

and add search filter:

->andFilterWhere(['like', 'what.name', $this->what]);

in index i have added this code and here is the problem, i think:

<?= GridView::widget([
        'dataProvider' => $dataProvider,
        'filterModel' => $searchModel,
        'columns' => [
            ['class' => 'yii\grid\SerialColumn'],           
            'id',
            [
                'label'=>'Name',
                'attribute' => 'what',
                'value' => function ($data) {
                    $str = '';
                    foreach($data->what as $name) {
                        $str .= $name->name.',';
                    }
                    return $str;
                },
            ],

data is like this: a,b,c,d for field of name! but i want ID and a then in next row ID and b and etc.
any help will be appreciated!

I dont know your code and I dont get the meaning, but I can answer in general.

A GridView is used to view Data in a Grid. A row in a GridView represents a dataset and presenting data in the form of a table.

foreach($data->what as $name) {
                    $str .= $name->name.',';
                }

I assume you want to display the Name attribute from the relation what. You can simply achieve this with the tablename.columnname syntax.

<?= GridView::widget([
    'dataProvider' => $dataProvider,
    'filterModel' => $searchModel,
    'columns' => [
        ['class' => 'yii\grid\SerialColumn'],           
        'id',
        [
            'label'=>'Name',
            'attribute' => 'what.name',
        ],

If you want to display the ID column additionally:

<?= GridView::widget([
    'dataProvider' => $dataProvider,
    'filterModel' => $searchModel,
    'columns' => [
        ['class' => 'yii\grid\SerialColumn'],           
        'id',
        [
            'label'=>'Name',
            'attribute' => 'what',
            'value' => function ($data) {
                $str = '';
                foreach($data->what as $name) {
                    $str .= ' ';
                    $str .= $name->id.'';
                    $str .= $name->name.',';
                }
                return $str;
            },
        ],

To be more precise (in Terms of your Problem). We have a datamodel with a junction table like the following simple book database.

Example:

If you want to display the names of the authors on the standard CRUD generated index Gridview, you can do something like this:

<?= GridView::widget([
    'dataProvider' => $dataProvider,
    'filterModel' => $searchModel,
    'columns' => [
        ['class' => 'yii\grid\SerialColumn'],

        'id',
        'book_name',
        [
            'label'=>'Author(s)',
            'value' => function ($dataProvider) {
                $str = '';
                foreach($dataProvider->authors as $name) {
                    $str .= ' ';
                    $str .= $name->id.' ';
                    $str .= $name->author_name.',';
                }
                return $str;
            },
        ],

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

with the result:

In addition, you can edit the Detail View to display such an information in an extra Gridview. The result can look like this.

To achieve this you have to:

1. add a data provider to your controller and pass the provider to the view
2. add a gridview widget in your view and connect the data provider
3. add a method to your model which crawls the data

view.php aka the view

use yii\grid\GridView;

// other code

<?= GridView::widget([
    'dataProvider' => $dataProvider,
        'columns' => [
        'id',
        [
            'attribute' => 'author.author_name',
            'header' => 'Author(s)',
        ],
    ],

]); ?>

BookController.php aka the controller

public function actionView($id)
{
    $dataProvider = Book::getAllAuthors($id);
    return $this->render('view', [
        'model' => $this->findModel($id),
        'dataProvider' => $dataProvider,
    ]);
}

Book.php aka the model

use \yii\data\ActiveDataProvider;

// other code

public static function getAllAuthors($id) {

    $query = BookAuthor::find()->where(['book_id' => $id]);
    $dataProvider = new ActiveDataProvider([
        'query' => $query,
    ]);

    return $dataProvider;

}