public class LoggerHelper
    {
        private static Queue<string> qMsg = null;
        private static string logFilePath = @"D:\log\"+ DateTime.Now.ToString("yyyy-MM-dd") + ".txt";//当然也可以改成读取配置文件


        static LoggerHelper()
        {
            qMsg = new Queue<string>();
            //存入日志
            Run();
        }

        public static void WriteLog(string strLog)
        {
            if (string.IsNullOrEmpty(strLog))
            {
                return;
            }
            strLog = strLog.Replace("\n", "\r\n");

            if (!File.Exists(logFilePath))
            {
                File.Create(logFilePath).Dispose();
            }
            using (StreamWriter sw = File.AppendText(logFilePath))
            {
                sw.WriteLine("[" + DateTime.Now.ToString("yyyy/MM/dd hh:mm:ss") + "]  " + strLog);
            }
        }

        public static void Run()
        {
            ThreadPool.QueueUserWorkItem(a =>
            {
                while (true)
                {
                    string tmsg = string.Empty;
                    lock (qMsg)
                    {
                        if (qMsg.Count > 0)
                            tmsg = qMsg.Dequeue();
                    }
                    if (!String.IsNullOrEmpty(tmsg))
                    {
                        WriteLog(tmsg);
                    }
                    if (qMsg.Count <= 0)
                    {
                        Thread.Sleep(1000);
                    }
                }
            });
        }

        public static void Run2()
        {
            Task.Run(() =>
            {
                while (true)
                {
                    string tmsg = string.Empty;
                    lock (qMsg)
                    {
                        if (qMsg.Count > 0)
                            tmsg = qMsg.Dequeue();
                    }
                    if (!String.IsNullOrEmpty(tmsg))
                    {
                        WriteLog(tmsg);
                    }
                    if (qMsg.Count <= 0)
                    {
                        Thread.Sleep(1000);
                    }
                }
            });
        }

        public static void WriteLogAsync(string strlog)
        {
            lock (qMsg)
            {
                qMsg.Enqueue(strlog);
            }
        }

        public static void WriteLogAsync(string filepath, string strlog)
        {
            if (string.IsNullOrEmpty(filepath))
            {
                WriteLogAsync(strlog);
            }
            else
            {
                logFilePath = filepath;
                lock (qMsg)
                {
                    qMsg.Enqueue(strlog);
                }
            }
        }
    }

  static void Main(string[] args)
        {
            string filepath=@"F:\log\"+ DateTime.Now.ToString("yyyy-MM-dd") + ".txt";
            Parallel.For(0,999,index=>{
                string msg1 = "test" + index.ToString();
                LoggerHelper.WriteLogAsync("", msg1);
            });

            Console.ReadLine();
        }