参考微信支付SDK的代码，抽取出来的winform存储记事本日志函数：

#region 存储日志        public string path = Application.StartupPath + "/logs";        private void WriteLog(string type, string className, string content)        {            if (!Directory.Exists(path))//如果日志目录不存在就创建            {                Directory.CreateDirectory(path);            }            string time = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");//获取当前系统时间            string filename = path + "/" + DateTime.Now.ToString("yyyy-MM-dd") + ".log";//用日期对日志文件命名            //创建或打开日志文件，向日志文件末尾追加记录            StreamWriter mySw = File.AppendText(filename);            //向日志文件写入内容            string write_content = time + " " + type + " " + className + ": " + content;            mySw.WriteLine(write_content);            //关闭日志文件            mySw.Close();        }        #endregion