ASP.NET 文件下载

using System;
using System.Web;
using System.IO;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    //TransmitFile实μ现?下?载?
    protected void Button1_Click(object sender, EventArgs e)
    {
        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μ现?下?载?
    protected void Button2_Click(object sender, EventArgs e)
    {
        string fileName = "asd.txt";//客í户§端?保￡存?的?文?件t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());
        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();
    }

    //WriteFile分?块é下?载?
    protected void Button3_Click(object sender, EventArgs e)
    {
        string fileName = "aaa.txt";//客í户§端?保￡存?的?文?件t名?
        string filePath = Server.MapPath("DownLoad/aaa.txt");//路·径?

        var fileInfo = new FileInfo(filePath);

        if (fileInfo.Exists == true)
        {
            const long chunkSize = 102400;//100K 每?次?读á取?文?件t，?只?读á取?100K，?这a样ù可é以?缓o解a服t务?器÷的?压1力|
            byte[] buffer = new byte[chunkSize];

            Response.Clear();
            FileStream iStream = File.OpenRead(filePath);
            long dataLengthToRead = iStream.Length;//获?取?下?载?的?文?件t总ü大ó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á取?的?大ó小?
                Response.OutputStream.Write(buffer, 0, lengthRead);
                Response.Flush();
                dataLengthToRead = dataLengthToRead - lengthRead;
            }
            Response.Close();
        }
    }

    //流÷方?式?下?载?
    protected void Button4_Click(object sender, EventArgs e)
    {
        string fileName = "aaa.txt";//客í户§端?保￡存?的?文?件t名?
        string filePath = Server.MapPath("DownLoad/aaa.txt");//路·径?

        //以?字?符?流÷的?形?式?下?载?文?件t
        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a浏ˉ览à器÷下?载?文?件t而?不?是?打ò开a
        Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
        Response.BinaryWrite(bytes);
        Response.Flush();
        Response.End();

    }
}