C#ASP.NET中四种文件下载方法

 无意中在论坛上看到的，保存下，以后可以备用
 ，特别注意文件分块下载，需要使用Response.Flush()方法，调用Flush方法将缓冲的响应发送到请求客户端
 //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=8月份报表.zip");
     string filename = Server.MapPath("DownLoad/8月份报表.zip");
     //指定编码 防止中文文件名乱码
     Response.HeaderEncoding = System.Text.Encoding.GetEncoding("gb2312");
     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(); www.2cto.com
     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();
 }