用TextWriterTraceListener實現建議log文件記錄

log4net之類3方組件確實很方便，但是想寫個小小的demo之類的程序，有點用不起啊。

微軟自帶的TraceListener要實現一個簡易的日志幫助類還是很簡單的，直接上代碼，自己備用，也希望對同樣煩惱的哥們有用：

using System;using System.Collections.Generic;using System.IO;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Diagnostics;namespace TestExPRessionLambda{    public class Logger    {        /// <summary>        /// 默認路徑        /// </summary>        public static readonly string RootPath = AppDomain.CurrentDomain.BaseDirectory + "log";        /// <summary>        /// 默認文件名格式        /// </summary>        public static readonly string FileFormat = DateTime.Now.ToString("yyyy-MM-dd") + ".log";        /// <summary>        /// 默認Trace監聽        /// </summary>        public static TextWriterTraceListener traceListener;        /// <summary>        /// 靜態實例        /// </summary>        private static readonly Logger instance = new Logger();        static Logger()        {            if (!Directory.Exists(RootPath))            {                Directory.CreateDirectory(RootPath);            }            string logFile = RootPath.TrimEnd('//') + "http://" + FileFormat;            //if (!File.Exists(logFile))            //{            //    File.Create(logFile);            //}            //這里不用create文件，TextWriterTraceListener會自動創建了,謝謝樓下的哥們            Trace.AutoFlush = true;            traceListener = new TextWriterTraceListener(logFile);            Trace.Listeners.Add(traceListener);        }        /// <summary>        /// log輸出　　　　 /// 當然這里可以自己隨便擴充        /// </summary>        /// <param name="msg"></param>        public static void Log(string msg)        {            Trace.WriteLine(msg);        }    }}