一：TransmitFile文件，不需要打开关闭文件，直接插入传输流中
Response.ContentType="application/x-zip-compressed";
Response.AddHeader("Content-Disposition",
"attachment;filename=z.zip");
stringfilename=Server.MapPath("DownLoad/z.zip");
Response.TransmitFile(filename);
二：
客户端保存的文件名
stringfilePath=Server.MapPath("DownLoad/aaa.txt");//路径
FileInfofileInfo=newFileInfo(filePath);
Response.Clear();
Response.ClearContent();
Response.ClearHeaders();
Response.AddHeader("Content-Disposition","attachment;fileContent-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();
三：流方式
FileStreamfs=newFileStream(filePath,FileMode.Open);
byte[]bytes=newbyte[(int)fs.Length];
fs.Read(bytes,0,bytes.Length);
fs.Close();
Response.ContentType="application/octet-stream";//通知浏览器文件而不是打开
Response.AddHeader("Content-Disposition","attachment; filename="+HttpUtility.UrlEncode(fileName,System.Text.Encoding.UTF8));
Response.BinaryWrite(bytes);
Response.Flush();
Response.End();