写入文件

string strPath = Server.MapPath("../NumberLog.txt");
                FileStream fs = new FileStream(strPath, FileMode.Append);
                StreamWriter sw = new StreamWriter(fs);
                //开始写入
                sw.Write(string+ " \r\n");
                //清空缓冲区
                sw.Flush();
                //关闭流
                sw.Close();
                fs.Close();