Yii文件上传

<?php
namespace frontend\controllers;

use Yii;
use yii\base\InvalidParamException;
use yii\web\BadRequestHttpException;
use yii\web\Controller;
use yii\filters\VerbFilter;
use yii\filters\AccessControl;
use common\models\LoginForm;
use frontend\models\PasswordResetRequestForm;
use frontend\models\ResetPasswordForm;
use frontend\models\SignupForm;
use frontend\models\ContactForm;
use app\models\ShangchuanModel;
use yii\web\UploadedFile;
class ShangchuanController extends Controller{
public  function  actionShangchuan(){

//echo $ar;
return  $this->render('shangchuan');

}
public function actionUpload()
{
$model = new ShangchuanModel();

if (Yii::$app->request->isPost) {
$model->imageFile = UploadedFile::getInstance($model, 'imageFile');
if ($model->upload()) {
// 文件上传成功
return;
}
}
else{
return $this->render('Shangchuan', ['model' => $model]);
}

}
}

?>