Property of non-object

Hi -

I am facing an issue that I am not able to fix. I have a workaround but I would be interested in understanding the root cause.

In my form I have multiple attributes but one of them is not displayed and populated in the controller like this:


  public function actionCreate()



     	$walkthrough = new Walkthrough();

	$post = new Post();

//Here is the device_id that I set in the controller and not in the form

        $post->device_id = 3;

        if ($walkthrough->load(Yii::$app->request->post()) && $post->load(Yii::$app->request->post()) && Model::validateMultiple([$walkthrough, $post])) {


        	$walkthrough->post_id = $post->id;

            if ($walkthrough->save(false)){

                $post->updateIndex();  <-- In this method I call a getter which uses the device_id


Model Post

    public function getDevice()


        return $this->hasOne(Device::className(), ['id' => 'device_id']);



 public function updateIndex(){

        $searchIndex = $this->searchIndex;

        if (!isset($searchIndex)){

            $searchIndex = new SearchIndex();


        $searchIndex->title = $this->generatePermalink($this->title);

        $searchIndex->summary = $this->summary;


	$device = $this->device->description;  <-- Error on this line

        $searchIndex->device = $device;

        $searchIndex->tags = $this->listTags;

        $searchIndex->post_id = $this->id;

        return $searchIndex->save();


I am getting the following error

2015-02-23 15:17:50 [][2][-][error][yii\base\ErrorException:8] exception ‘yii\base\ErrorException’ with message ‘Trying to get property of non-object’ in /home/www/common/models/Post.php:293

Stack trace:

#0 /home/www/common/models/Post.php(293): yii\base\ErrorHandler->handleError(8, ‘Trying to get p…’, ‘/home/…’, 293, Array)

#1 /home/www/backend/controllers/WalkthroughController.php(131): common\models\Post->updateIndex()

The workaround is to set the device_id in the _form and then it works, I can access the $this->device->description

Question is, Am i missing something obvious or am I doing something wrong.

Please ask me for more details if needed, I am really interested in knowing the cause.

Thank you


I think $this->device is null when there is the error.

“var_dump();die;” it ;)

You made my day, I missed the obvious, I did remove the id=3 in the device table hence the null.

Thanks so much!