public ActionResult DownloadFile(Guid id)
        {
            try
            {
                Document document = DocumentDao.GetDocumentById(id);
                string path = string.Format("{0}/{1}", Server.MapPath("/Documents"), document.ArchiveIdentity);
                return File(path, "application/octet-stream", Url.Content(document.FileName));
            }
            catch {
                return null;
            }
        }