Kartik Select2返回null

Question

i have a problem with Kartik Select2. When I want save multiple data in my controller, nothing is saved. And I remove foreach in controller, Yii return me error with information about $university_id IS NULL.

User Form

<?= $form->field($user_university, 'university_id')->widget(Select2::classname(),[
    'name' => 'university_id[]',
    'data' => ArrayHelper::map(
        \app\models\University::find()->asArray()->all(),
        'id',
        function ($university) {
            return $university['name'];
        }
    ),
    'size' => Select2::MEDIUM,
    'options' => ['placeholder' => 'Select a state ...', 'multiple' => true],
    'pluginOptions' => [
        'allowClear' => true
    ],
]); ?>

User Controller

 $user = new User();
    $user->scenario = User::SCENARIO_CREATE;
    $auth_assignment = new AuthAssignment();
    $user_company = new UserCompany();
    $user_university = new UserUniversity();
    $user_status = UserStatus::find()
        ->select('id')
        ->where(['name' => UserStatus::NON_AUTHORIZED_USER])
        ->one();

    if ($user->load(Yii::$app->request->post()) && $auth_assignment->load(Yii::$app->request->post())) {

        $user->auth_key = Yii::$app->getSecurity()->generateRandomString();
        $user->password_hash = Yii::$app->getSecurity()->generatePasswordHash($user->password);
        $user->password_reset_token = Yii::$app->getSecurity()->generateRandomString();
        $user->status_id = $user_status->id;
        $user->created_at = date('Y-m-d H:i:s');
        $user->updated_at = date('Y-m-d H:i:s');


        if ($user->save()) {
            $auth_assignment->user_id = $user->id;
            $auth_assignment->created_at = date('Y-m-d H:i:s');

            $universities = $user_university->university_id;
            foreach((array) $universities as $university)
            {
                $newUserUniversity = new UserUniversity();
                $newUserUniversity->user_id = $user->id;
                $newUserUniversity->university_id = $university;
                $newUserUniversity->created_at = date('Y-m-d H:i:s');
                $newUserUniversity->save(false);

            }...

User University Model Rule

public function rules()
{
    return [
        [['user_id', 'university_id', 'created_at'], 'required'],
        [['user_id', 'university_id','confirm'], 'integer'],
        [['created_at','university_id'], 'safe'],
        [['university_id'], 'exist', 'skipOnError' => true, 'targetClass' => University::className(), 'targetAttribute' => ['university_id' => 'id']],
        [['user_id'], 'exist', 'skipOnError' => true, 'targetClass' => User::className(), 'targetAttribute' => ['user_id' => 'id']],
    ];
}

Answer 1

Looking at your code i can't see where you are loading the data from the post request into the $user_university before you start looping on the university_id. You need to call $user_university->load(Yii::$app->request->post()), look the following piece of code from your script

if ($user->save()) {
   $auth_assignment->user_id = $user->id;
   $auth_assignment->created_at = date('Y-m-d H:i:s');

   // this below line will give you an empty string rather than 
   // the selected ids of the `university` that you selected 
   // in the multi-dropdown

   $universities = $user_university->university_id;  

and the very next line is the foreach((array) $universities as $university) in which you are trying to save which won't run even once, as there isnt any array loaded in the $unversities. So you can add a call before you get the array from the attribute, dont know if your requirements are to return the user with an error if the data is not loaded for the $user_university otherwise you need to add it to the main check

if ($user->load(Yii::$app->request->post()) && $auth_assignment->load(Yii::$app->request->post()) &&
$user->university->load(Yii::$app->request->post())) {

So your code should look like below

$user = new User();
$user->scenario = User::SCENARIO_CREATE;
$auth_assignment = new AuthAssignment();
$user_company = new UserCompany();
$user_university = new UserUniversity();
$user_status = UserStatus::find()
    ->select('id')
    ->where(['name' => UserStatus::NON_AUTHORIZED_USER])
    ->one();

//validate all models
$allModelsValid=$user->load(Yii::$app->request->post()) && $auth_assignment->load(Yii::$app->request->post()) && $user_university->load(Yii::$app->request->post());

if ($allModelsValid) {

    $user->auth_key = Yii::$app->getSecurity()->generateRandomString();
    $user->password_hash = Yii::$app->getSecurity()->generatePasswordHash($user->password);
    $user->password_reset_token = Yii::$app->getSecurity()->generateRandomString();
    $user->status_id = $user_status->id;
    $user->created_at = date('Y-m-d H:i:s');
    $user->updated_at = date('Y-m-d H:i:s');


    if ($user->save()) {
        $auth_assignment->user_id = $user->id;
        $auth_assignment->created_at = date('Y-m-d H:i:s');

        $universities = $user_university->university_id;
        foreach((array) $universities as $university)
        {
            $newUserUniversity = new UserUniversity();
            $newUserUniversity->user_id = $user->id;
            $newUserUniversity->university_id = $university;
            $newUserUniversity->created_at = date('Y-m-d H:i:s');
            $newUserUniversity->save(false);

        }...

Also apart from above i dont find a reason to use the name as university_id[] for the dropdown rather than university_id