C#的几种下载文件方法

 public void meth1()
    {
        /* 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);

    }
    public void meth2()
    {
        /* using System.IO; */
        string fileName = "asd.txt";//客户端保存的文件名 
        string filePath = Server.MapPath("DownLoad/" + fileName);//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());
        Response.AddHeader("Content-Transfer-Encoding", "binary");
        Response.ContentType = "application/octet-stream";
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
        Response.WriteFile(fileInfo.FullName);
        Response.Flush();
        Response.End();

    }
    public void meth3()
    {
        string fileName = "aaa.txt";//客户端保存的文件名 
        string filePath = Server.MapPath("DownLoad/" + fileName);//路径 
        System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);
        if (fileInfo.Exists == true)
        {
            const long ChunkSize = 102400;//100K 每次读取文件，只读取100K，这样可以缓解服务器的压力 
            byte[] buffer = new byte[ChunkSize];
            Response.Clear();
            System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);
            long dataLengthToRead = iStream.Length;//获取下载的文件总大小 
            Response.ContentType = "application/octet-stream";
            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName)); while (dataLengthToRead > 0 && Response.IsClientConnected)
            {
                int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小 Response.OutputStream.Write(buffer, 0, lengthRead); 
                Response.Flush();
                dataLengthToRead = dataLengthToRead - lengthRead;
            }
            Response.Close();
        }

    }

    public void meth4()
    {
        string fileName = "aaa.txt";//客户端保存的文件名 
        string filePath = Server.MapPath("DownLoad/" + fileName);//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();
    }