C# 文件下载四方法

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.IO;



public partial class _Default : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{



}



//TransmitFile实现下载

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实现下载

protected void Button2_Click(object sender, EventArgs e)

{

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());

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分块下载

protected void Button3_Click(object sender, EventArgs e)

{

string fileName = "aaa.txt";//客户端保存的文件名

string filePath = Server.MapPath("DownLoad/aaa.txt");//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();

}

}



//流方式下载

protected void Button4_Click(object sender, EventArgs e)

{

string fileName = "aaa.txt";//客户端保存的文件名

string filePath = Server.MapPath("DownLoad/aaa.txt");//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();



}

}