Call to a member function saveAs() on null(does't work skipOnEmpty)

问题

I can't update a page without of upload image.Even if I write skipOnEmpty in the rules it doesn't work . What do I wrong?

This is a controller

    if ($model->load(Yii::$app->request->post())){
        //represent the uploaded file as an instance
        $model->imageFile = UploadedFile::getInstance($model, 'imageFile');

        //save path to image in db
        $model->image = '/images/' . $model->imageFile->baseName . '.' . $model->imageFile->extension;
        //save changes in db 
        $model->save();
      //upload image on server
        $model->upload();
 Yii::$app->session->setFlash('success', 
                "Product is successfully updated!");
        return $this->redirect(['view', 'id' => $model->id]);
    } else {
        return $this->render('update', [

            'model' => $model,
        ]);
    }
}

This is a model

public function rules()
{
    return [
        [['name', 'category', 'code', 'price', 'availability', 'brand', 'description'], 'required'],
        [['category', 'code', 'availability', 'is_new', 'is_recommended', 'status'], 'integer'],
        [['price'], 'number'],
        [['description'], 'string'],
        [['name','image', 'brand'], 'string', 'max' => 255],
        [['imageFile'], 'file', 'skipOnEmpty' => true, 'extensions' => 'png, jpg'],
    ];
}

uploading of a file to the server

public function upload()
{
    if ($this->validate()) {
        $this->imageFile->saveAs('images/' . $this->imageFile->baseName . '.' . $this->imageFile->extension);
        return true;
    } else {
        return false;
    }
}

回答1:

change your controller code like below:

if ($model->load(Yii::$app->request->post())){
        //represent the uploaded file as an instance
        $model->imageFile = UploadedFile::getInstance($model, 'imageFile');

        //save path to image in db
        if($model->imageFile){
        $model->image = '/images/' . $model->imageFile->baseName . '.' . $model->imageFile->extension;
        }
        //save changes in db 
        $model->save();
      //upload image on server
        if($model->imageFile){
                $model->upload();
            }
 Yii::$app->session->setFlash('success', 
                "Product is successfully updated!");
        return $this->redirect(['view', 'id' => $model->id]);
    } else {
        return $this->render('update', [

            'model' => $model,
        ]);
    }
}

Set a hidden field in your upload form like below:

<?php $form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]); ?>


    <?= $form->field($model, 'imageFile')->fileInput() ?>
    <?if(!$model->isNewRecord):
            echo Html::activeHiddenInput($model, 'imageFile');
        endif;
    ?>

来源：https://stackoverflow.com/questions/37746082/call-to-a-member-function-saveas-on-nulldoest-work-skiponempty