Modified DailyTextLogListener

gistfile1.cs

using System;
using System.Diagnostics;
using System.IO;
using System.Security.Permissions;

namespace Darkthread
{
    /// <summary>
    /// 會依每天日期獨立個別檔案的TextWriterTraceListener
    /// </summary>
    [HostProtection(SecurityAction.LinkDemand, Synchronization = true)]
    public class DailyTextLogListener : TraceListener
    {
        private TextWriterTraceListener _textWriterTraceListener;

        /// <summary>
        /// 入Log路徑設定，可使用{0:yyyyMMdd}依日期動態變化
        /// </summary>
        public string LogPathPattern { get; set; }
        /// <summary>
        /// 建構式，傳入Log路徑設定，可使用{0:yyyyMMdd}依日期動態變化
        /// </summary>
        /// <param name="logPathPattern"></param>
        public DailyTextLogListener(string logPathPattern)
        {
            LogPathPattern = logPathPattern;
            _textWriterTraceListener = new TextWriterTraceListener(GetDailyFilePath());
        }
        /// <summary>
        /// 由Writer取出目前使用的Log檔路徑
        /// </summary>
        /// <returns></returns>
        private string GetCurrentFilePath()
        {
            if (_textWriterTraceListener.Writer == null) return null;
            return ((_textWriterTraceListener.Writer as StreamWriter).BaseStream as FileStream).Name;
        }
        /// <summary>
        /// 由當天日期及LogPathPattern設定決定當時應使用的Log檔路徑
        /// </summary>
        /// <returns></returns>
        private string GetDailyFilePath()
        {
            //未指定LogPathPattern時給予預設值
            if (string.IsNullOrEmpty(LogPathPattern))
                LogPathPattern = ".\\{0:yyyyMMdd}.log";
            return string.Format(LogPathPattern, DateTime.Now);
        }
        /// <summary>
        /// 確認目前使用的Writer有指向正確的檔案
        /// </summary>
        private void EnsureDailyLogPath()
        {
            //檢查目前的路徑是否為正確的路徑
            string dailyLogPath = GetDailyFilePath();
            if (dailyLogPath != GetCurrentFilePath())
            {
                //取出目錄部分
                string dirPath = Path.GetDirectoryName(dailyLogPath);
                //先確保路徑存在，若不存在則建立之
                if (!Directory.Exists(dirPath))
                    Directory.CreateDirectory(dirPath);
                //關閉目前使用的Log檔案
                _textWriterTraceListener.Dispose();

                // **********************
                _textWriterTraceListener = new TextWriterTraceListener(dailyLogPath);
                // **********************
            }
        }
        //覆寫Write，寫入資料前確認檔案路徑
        public override void Write(string message)
        {
            EnsureDailyLogPath();
            _textWriterTraceListener.Write(message);
        }
        //覆寫WriteLine，寫入資料前確認檔案路徑
        public override void WriteLine(string message)
        {
            EnsureDailyLogPath();
            _textWriterTraceListener.WriteLine(message);
        }
        public override void Close()
        {
            _textWriterTraceListener.Close();
            base.Close();
        }
        protected override void Dispose(bool disposing)
        {
            if (disposing) _textWriterTraceListener.Dispose();
            base.Dispose(disposing);
        }
    }
}