asp.net mvc上传文件

前台cshtml中的代码
<form action="/godown/upload" method="post" enctype="multipart/form-data" hidden="hidden">
                            <input type="file" name="file" id="fileUploadBtn" accept="application/vnd.ms-excel" />
                            <input type="submit" id="fileSubmit"/>
                        </form>

后台对应controller中的处理方法
[HttpPost]
        public void upload(HttpPostedFileBase file)
        {
            var fileName = file.FileName;
            var filePath = Server.MapPath(string.Format("~/{0}", "File"));
            file.SaveAs(Path.Combine(filePath, fileName));
        }