MVC上传文件

@using (Html.BeginForm("ModifySave", "ArticlesInfo", FormMethod.Post, new { enctype = "multipart/form-data" }))
    {
@Html.TextBoxFor(model => model.Title, new { @class = "boxtext" })
<br />
@Html.TextAreaFor(model => model.Contents, new { cols = "50", rows = "20", sign = "Contents" })
<br />
<input type="file" name="Img" class="boxtext" />
<br />
<input type="submit" value="保存" class="boxbut" />
}

[HttpPost]
        [ValidateInput(false)]
        public ActionResult ModifySave(Models.ArticlesInfo data, HttpPostedFileBase Img)
        {
            Models.ArticlesInfo model = db.ArticlesInfos.Single(c => c.ID == data.ID);
            model.Title = data.Title;
            model.Contents = data.Contents;
            if (Img != null && Img.ContentLength > 0)
            {
                string fileName = DateTime.Now.ToString("yyyyMMddHHmmss") + System.IO.Path.GetExtension(Img.FileName);
                string filePath = Server.MapPath("~/UploadFile/") + fileName;
                Img.SaveAs(filePath);
                model.Img = "/UploadFile/" + fileName;
            }
            db.SaveChanges();
            return RedirectToAction("Modify", new { id = model.ID, tid = model.TypeID });
        }