public ActionResult Download(string src, string contentType) { if (string.IsNullOrEmpty(src)) { return(new EmptyResult()); } src = Base64Helper.DecodingString(src); if (string.IsNullOrEmpty(contentType)) { string text = FileHelper.GetContentType(Path.GetExtension(src)); if (text.StartsWith(".")) { text = text.Replace(".", ""); } contentType = FileHelper.GetContentType(text); } return(File(Server.MapPath("~/" + src), contentType)); }