日志记录类

代码：

 namespace Assist.Log
{
    public static class DownLog
    {
        private static string FileName = string.Empty;
        private static StreamWriter swLog = null;
        private static readonly string ExtName = "_DownLog.txt";//日志类型
        private static readonly string ConfigLogPath = "LogPath";//日志储存路径
        private static readonly string ConfigLogSaveDate = "LogSaveDay";//储存天数
        private static System.Collections.Generic.Queue<string> LogBuffer;
        private static ThreadStart job = new ThreadStart(WriterLog);
        private static Thread thread = new Thread(job);

        /// <summary>
        /// 存放日志目录
        /// </summary>
        private static string _LogPath = null;
        private static string LogPath
        {
            get
            {
                if (_LogPath == null)
                {
                    if (ConfigurationManager.AppSettings[ConfigLogPath] != null)
                    {
                        _LogPath = ConfigurationManager.AppSettings[ConfigLogPath];
                    }
                    else
                    {//默认值
                        //_LogPath = AppDomain.CurrentDomain.BaseDirectory + @"log\";//App应用
                        _LogPath = AppDomain.CurrentDomain.BaseDirectory + @"bin\Log\";//Web应用
                    }
                }

                return _LogPath;
            }
        }

        /// <summary>
        /// 日志保存期(天)
        /// </summary>
        private static int _SaveDay = -1;
        private static int SaveDay
        {
            get
            {
                if (_SaveDay == -1)
                {
                    if (ConfigurationManager.AppSettings[ConfigLogSaveDate] != null)
                    {
                        _SaveDay = int.Parse(ConfigurationManager.AppSettings[ConfigLogSaveDate]);
                    }
                    else
                    {//默认值
                        _SaveDay = 31;
                    }
                }

                return _SaveDay;
            }
        }

        private static void WriterLog()
        {
            while (true)
            {
                TextWriter twLog = GetStreamWriter();
                while (LogBuffer!=null && LogBuffer.Count > 0)
                {
                    twLog.Write(LogBuffer.Dequeue() + "\r\n");
                    twLog.Flush();
                    //Thread.Sleep(50);
                }
                Thread.Sleep(30);
            }
        }


        private static StreamWriter GetStreamWriter()
        {
            if ((FileName != System.DateTime.Now.ToString("yyyy_MM_dd")) || swLog == null)
            {
                if ((swLog != null)) swLog.Close();
                if (!Directory.Exists(LogPath))
                {
                    Directory.CreateDirectory(LogPath);
                }
                FileName = System.DateTime.Now.ToString("yyyy_MM_dd");
                DelLog(LogPath, SaveDay);
                try
                {
                    swLog = new StreamWriter(Path.Combine(LogPath, FileName + ExtName), true, System.Text.Encoding.UTF8, 1024);
                }
                catch
                {
                    if ((swLog != null))
                    {
                        swLog.Close();
                        System.Threading.Thread.Sleep(30);
                        swLog = new StreamWriter(Path.Combine(LogPath, FileName + ExtName), true, System.Text.Encoding.UTF8, 1024);
                    }
                }
            }
            return swLog;
        }


        /// <summary>
        /// 系统日志信息记录
        /// </summary>
        /// <param name="Info">记录的内容（用;号分开）</param>
        public static void WriteLog(string Info)
        {
            if (LogBuffer == null)
            {
                LogBuffer = new System.Collections.Generic.Queue<string>();
                thread.IsBackground = true;
                thread.Start();
            }
            if (!string.IsNullOrEmpty(Info))
            {
                LogBuffer.Enqueue(Info);
            }
        }
        
        /// <summary>
        /// 自动删除过期日志文件
        /// </summary>
        /// <param name="path">路径</param>
        /// <param name="day">超出的天数</param>
        private static void DelLog(string path, double day)
        {
            if (SaveDay > 0)
            {
                DirectoryInfo folder = new DirectoryInfo(path);
                FileInfo[] chldFiles = folder.GetFiles("*" + ExtName);
                foreach (FileInfo chlFile in chldFiles)
                {
                    try
                    {
                        if (chlFile.Name.Replace(ExtName, "").CompareTo(DateTime.Now.AddDays(-day).ToString("yyyy_MM_dd")) <= 0) chlFile.Delete();
                    }
                    catch { }
                }
            }
        }
    }
}

调用：

Assist.Log.DownLog.WriteLog(“日志内容，要求string类型”);