关于文件下载的问题！急！！！！！！！！

Question

 private void FileDownload(string str)
    {
        String FullFileName = Server.MapPath(str);
        FileInfo DownloadFile = new FileInfo(FullFileName);
        Response.Clear();
        Response.ContentType = "application/octet-stream";
        Response.AddHeader("Content-Disposition", "attachement;filename=" + FullFileName);         long fileSize = DownloadFile.Length;
        Response.ContentType = "application/octet-stream ";
          Response.AddHeader("Content-Disposition ", fileSize.ToString());
        Response.TransmitFile(FullFileName, 0, fileSize);
        Response.Flush();
        Response.Close(); 
      Response.End();
    } 
为什么我下载txt文件不下载，而是直接打开呢？？？

Answer 1

//通知浏览是下载。。不是打开
 Response.AddHeader("Content-Disposition", "attachment;   filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));/字符流方式下载文件
        protected void Button4_Click(object sender, EventArgs e)
        {
            string fileName = "ce2.rar";//客户端保存的文件名
            string filePath = Server.MapPath("keji.rar");//路径            //以字符流的形式下载文件
            FileStream fs = new FileStream(filePath, FileMode.Open);
            byte[] bytes = new byte[(int)fs.Length];
            fs.Read(bytes, 0, bytes.Length);
            fs.Close();
            Response.ContentType = "application/octet-stream";
            //通知浏览器下载文件而不是打开
            Response.AddHeader("Content-Disposition", "attachment;   filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
            Response.BinaryWrite(bytes);
            Response.Flush();
            Response.End();
}