string fileName = "开发计划.mpp";//客户端保存的文件名          
            string filePath = Server.MapPath("zyd??开发计划.mpp"); //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();