在ASP.NET中下载文件

//TransmitFile实现下载
    protected void Button1_Click(object sender, EventArgs
e)
    {
        /*
       
微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite
       
下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。
        代码如下：
        */
        Response.ContentType = "application/x-zip-compressed";
       
Response.AddHeader("Content-Disposition",
"attachment;filename=z.zip");
        string filename =
Server.MapPath("DownLoad/z.zip");
       
Response.TransmitFile(filename);
    }
    //WriteFile实现下载
    protected void Button2_Click(object sender,
EventArgs e)
    {
        /*
        using System.IO;
        */
        string fileName = "asd.txt";//客户端保存的文件名
       
string filePath = Server.MapPath("DownLoad/aaa.txt");//路径
        FileInfo fileInfo = new FileInfo(filePath);
       
Response.Clear();
        Response.ClearContent();
       
Response.ClearHeaders();
        Response.AddHeader("Content-Disposition",
"attachment;filename=" + fileName);
       
Response.AddHeader("Content-Length", fileInfo.Length.ToString());
      &