public function upload($id)
 {
     if ($this->validate()) {
         if (!is_null($this->listFile)) {
             ImageManager::delProductImages($id, 'list');
             ImageManager::addProductImage($id, 'list', $this->listFile);
         }
         if (!is_null($this->detailFile)) {
             ImageManager::addProductImage($id, 'det', $this->detailFile);
         }
         return true;
     } else {
         return false;
     }
 }