C# 下载文件

方法一：以二进制流的形式下载

            string fileName = this.nameSave.Value;//客户端保存的文件名      
            //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);//将流写到回发报文中
            Response.Flush();
            Response.End();//关闭缓冲区，将报文回立即回发给客户端

 方法二：直接输出文件

            string FileName = "文件名.xls";
            Response.Clear();
            Response.Buffer = true;
            EnableViewState = false;
            Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8));
            Response.WriteFile(FileName);
            Response.Flush();
            Response.Close();
            Response.End();