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/aaa.zip");

  Response.TransmitFile(filename);

  }

  //WriteFile实现下载

  protected void Button2_Click(object sender, EventArgs e)

  {

  /*

  using System.IO;

  */

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

  string filePath=Server.MapPath("DownLoad/aaa.zip");//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.zip";//客户端保存的文件名

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

  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.zip";//客户端保存的文件名

  string filePath = Server.MapPath("DownLoad/aaa.zip");//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(fileName, System.Text.Encoding.UTF8));

  Response.BinaryWrite(bytes);

  Response.Flush();

  Response.End();

  }