Yii2: How to use map() to show two fields in a Select2? - yii2

Question

I am using a Select2 widget for Yii2. It shows a list with the ids of the users.
I need to show two fields defined in my model called Users: first_name_user and last_name_user. Like this:
Daniel Gates
John Connor
John Doe
Maria Key
But I don't know how use map() to show more than one field.
<?= $form
->field($model, 'id_user')
->widget(\common\widgets\Select2::classname(), [
'items' => \yii\helpers\ArrayHelper::map(\app\models\Users::find()->orderBy('name_user')->all(), 'id_user', 'name_user')
])
?>

Answer 1

Model
Add use app\models\Users; and use yii\helpers\ArrayHelper; at top.
public function userList()
{
$userList = [];
$users = Users::find()->orderBy('first_name_user')->all();
$userList = ArrayHelper::map($users, 'id_user', function ($user) {
return $user->first_name_user.' '.$user->last_name_user;
});
return $userList;
}
_form
<?= $form->field($model, 'id_user')->widget(Select2::className(), [
'data' => $model->userList(),
'options' => ['placeholder' => 'Select User'],
]) ?>

Answer 2

You need to use data option instead of items for Select2.
You need to modify your query to show the concatenated first_name_user and last_name_user as an alias and then return it along with the id column to be used in Select2 by ArrayHelper::map().
It's better to add a function to the model you are using to populate the form and return the results from there to the ArrayHelper::map().
Your query should look like
function userList(){
return \app\models\Users::find()
->select([new \yii\db\Expression('[[id_user]],CONCAT([[first_name_user]]," ",[[last_name_user]]) as full_user_name')])
->orderBy('name_user')
->all();
}
Your form field should look like below
<?=
$form->field($model, 'id_user')->widget(Select2::className(), [
'data' => \yii\helpers\ArrayHelper::map($model->userList(), 'id_user', 'full_user_name'),
'options' => [
'placeholder' => 'Select User',
'id' => 'id_user'
],
'theme' => Select2::THEME_DEFAULT,
'pluginOptions' => [
'allowClear' => true
],
]);
?>