用TextWriterTraceListener实现建议log文件记录log4net之类3方组件确实很方便，但是想写个小小的demo之类的程序，有点用不起啊。
微软自带的TraceListener要实现一个简易的日志帮助类还是很简单的，直接上代码，自己备用，也希望对同样烦恼的哥们有用：
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> /// 默认路径 /// </summary> public static readonly string RootPath = AppDomain.CurrentDomain.BaseDirectory + "log"; /// <summary> /// 默认文件名格式 /// </summary> public static readonly string FileFormat = DateTime.Now.ToString("yyyy-MM-dd") + ".log"; /// <summary> /// 默认Trace监听 /// </summary> public static TextWriterTraceListener traceListener; /// <summary> /// 静态实例 /// </summary> private static readonly Logger instance = new Logger(); static Logger() { if (!Directory.Exists(RootPath)) { Directory.CreateDirectory(RootPath); } string logFile = RootPath.TrimEnd('\\') + "\\" + FileFormat; //if (!File.Exists(logFile)) // //这里不用create文件，TextWriterTraceListener会自动创建了,谢谢楼下的哥们 Trace.AutoFlush = true; traceListener = new TextWriterTraceListener(logFile); Trace.Listeners.Add(traceListener); } /// <summary> /// log输出 /// 当然这里可以自己随便扩充 /// </summary> /// <param name="msg"></param> public static void Log(string msg) { Trace.WriteLine(msg); } }}