asp.net下载文件几种方式

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 = 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.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, 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();

      }