asp.net实现文件下载(wap手机下载)

这个问题困扰了我两天，手机下载
 protected void Page_Load(object sender, EventArgs e)
    {
        string filename = Server.UrlDecode(Request["upload"]);
        string filePath = Server.MapPath("upload/" + filename);//路径
        FileDownload(filePath);
    }
/// <summary>
    /// 文件下载
    /// </summary>
    /// <param name="FullFileName"> </param>
    private void FileDownload(string FullFileName)
    {
        try
        {
            FileInfo DownloadFile = new FileInfo(FullFileName);
            if (DownloadFile.Exists)
            {
                Response.Clear();
                Response.ClearHeaders();
                Response.Buffer = false;
                //Response.ContentType = "application/octet-stream";//通知浏览器下载文件而不是打开
                Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(DownloadFile.FullName, System.Text.Encoding.UTF8));
                Response.AppendHeader("Content-Length", DownloadFile.Length.ToString());
    &nb