一：TransmitFile文件下载，，不需要打开*文件，直接插入传输流中
Response.ContentType = "application/x-zip-compressed";
Response.AddHeader("Content-Disposition",
"attachment;filename=z.zip");
string filename = Server.MapPath("DownLoad/z.zip");
Response.TransmitFile(filename);
二：
}
//
第二：WriteFile下载文件
string fileName ="asd.txt";//
客户端生存的文件名
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();
三：流方法下载
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();
四：WriteFile 分块下载 本身百度去