C#实现下载的几种方式举例

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 = ;//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(fil  eName));
  while (dataLengthToRead >  && Response.IsClientConnected)
  {
 int lengthRead = iStream.Read(buffer, , Convert.ToInt32(ChunkSize));//读取的大小
 Response.OutputStream.Write(buffer, , 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, , 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(fi  leName, System.Text.Encoding.UTF8));
 Response.BinaryWrite(bytes);
 Response.Flush();
 Response.End();
}
}