写入日志小技巧

 EventLog log = new EventLog("Wodongni.Com");
            //  首先应判断日志来源是否存在，一个日志来源只能同时与一个事件绑定s
            if (!EventLog.SourceExists("New Application1"))
                EventLog.CreateEventSource("New Application1", "Wodongni.Com");
            try
            {
                log.Source = "New Applications1";
                log.WriteEntry("处理信息1", EventLogEntryType.Information);
                log.WriteEntry("处理信息2", EventLogEntryType.Information);
                throw new System.IO.FileNotFoundException("readme.txt文件未找到");
            }
            catch (System.IO.FileNotFoundException exception)
            {
                log.WriteEntry(exception.Message, EventLogEntryType.Error);
            }

        private static void WriteMsg(string msg)
        {
            string txtPath = System.AppDomain.CurrentDomain.BaseDirectory+"\\demo.txt";
            StreamWriter sw = new StreamWriter(txtPath, true, System.Text.Encoding.Default);
             sw.WriteLine("time:"+DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"));
            sw.WriteLine(msg);
            sw.Close();
        }

http://www.cnblogs.com/nokiaguy/archive/2009/02/26/1398708.html