FileStream fileStream = new FileStream(@"c:\123.ini", FileMode.Open);
            long fileSize = fileStream.Length;
            Context.Response.ContentType = "application/octet-stream";

            Context.Response.AddHeader("Content-Disposition", "attachment; filename=\"" + HttpUtility.UrlEncode("ini.ini", System.Text.Encoding.UTF8) + "\"");
            Context.Response.AddHeader("Content-Length", fileSize.ToString());
            byte[] fileBuffer = new byte[fileSize];
            fileStream.Read(fileBuffer, 0, (int)fileSize);
            fileStream.Close();
            Context.Response.BinaryWrite(fileBuffer);
            Context.Response.End();