public class HDot264Result : ActionResult
    {
        public string FilePhysicalPath { private get; set; }

        public override void ExecuteResult(ControllerContext context)
        {
            var file = new FileInfo(FilePhysicalPath);
            if (file.Exists)
            {
                context.HttpContext.Response.AddHeader("Content-Disposition", "attachment; filename=" + file.Name);

                //var stream = file.OpenRead();
                //var bytes = new byte[stream.Length];
                //stream.Read(bytes, 0, (int)file.Length);
                //context.HttpContext.Response.BinaryWrite(bytes);

                FileStream fs = new FileStream(FilePhysicalPath, FileMode.Open, FileAccess.Read);
                BinaryReader br = new BinaryReader(fs);
                Byte[] bytes = br.ReadBytes((Int32)fs.Length);
                br.Close();
                fs.Close();
                context.HttpContext.Response.OutputStream.Write(bytes, 0, bytes.Length);
            }

        }
    }