一个文件上传案例，就是上传不了 [ 2.0 版本 ]

view层

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

        <?= $form->field($model, 'title')->textInput(['maxlength' => true]) ?>

        <?= $form->field($model, 'grade_id')->dropDownList(
            Grade::find()
                ->select(['grade','id'])
                ->orderBy('id')
                ->indexBy('id')
                ->column(),
            ['prompt'=>'请选择班级']
        ) ;?>
        
 <?= $form->field($model, 'path')->fileInput() ?>
 
  <div class="form-group">
            <?= Html::submitButton('上传', ['class' => 'btn btn-primary']) ?>
        </div>

        <?php ActiveForm::end(); ?>

Controller层

 public function actionCreate()
    {
            $model = new Video();
            if (Yii::$app->request->isPost )
            {
                $model->author_id = \Yii::$app->user->identity->id ;
                $model->create_time = date('Y-m-d');
                $model->status = 0;
                $pathName = UploadedFile::getInstance($model, "path");
                var_dump($pathName);
                //文件名
                $fileName = date("HiiHsHis").mt_rand(1100,9900). "." . $pathName->extension;
                //文件上传存放的目录
                $dirPath = "../../upload/videos/".date("Ymd");
                $dirPathDb = "=upload/videos/".date("Ymd");
//                var_dump($fileName);
//                var_dump($dirPath);
                if (!is_dir($dirPath))
                    mkdir($dirPath);
                //文件目录+文件名
                $dir = $dirPathDb."/". $fileName;
//                var_dump($dir);
                //保存到数据库
                //$model->path=$dir;
                //添加入库
//                $res = Yii::$app->db->createCommand()
//                    ->insert('video',['path'=>$dir,'author_id'=>\Yii::$app->user->identity->id,'create_time'=>date('Y-m-d'),
//                    'status'=>0,'title'=>$model->title,'tags'=>$model->tags,'grade_id'=>$model->grade_id,'subject_id'=>$model->subject_id,
//                        'img_up'=>$model->img_up
//                    ])
//                    ->execute();
                //echo 5;
//                if($pathName->saveAs($dir) === true){
//                    $model->path=$dir;
//                    echo 3;
//                }

                $pathName->saveAs($dirPath,true);
                $model->path = $dirPathDb."/". $fileName;

                if ($model->save()) {
                    return $this->redirect(['view', 'id' => $model->id]);
                }
             else {
                return $this->render('create', [
                    'model' => $model,]);
            }
            }
         else {
                echo 2;

             return $this->render('create', [
                'model' => $model,
            ]);
        }
    }   

可是就是上传不上去

测试了很久