C#实现下载Demo

 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(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.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(fileName, System.Text.Encoding.UTF8));
         Response.BinaryWrite(bytes);
         Response.Flush();
         Response.End();

     }
 }