Response.ClearContent();
string fPath = Path.Combine(path, filename);
FileStream fFileStream = new FileStream(fPath, FileMode.Open, FileAccess.Read);
long fFileSize = fFileStream.Length;
Context.Response.ContentType = "application/octet-stream";
Context.Response.AddHeader("Content-Disposition", "attachment; filename=\"" + HttpUtility.UrlEncode(Path.GetFileName(fPath), System.Text.Encoding.UTF8) + "\"");
Context.Response.AddHeader("Content-Length", fFileSize.ToString());

Server.Transfer ("./上传空间/" + filename);

手机下载文件后为KB.电脑下载正常