TraceListener creates huge log files

If you've used the .Net trace listeners, you'll know that they just keep appending to the file specified in the App.Config file, this can lead to some massive log files! Here's a simple TraceListener that logs to a new file for every day.

using System;
using System.Text;
using System.IO;
using System.Diagnostics;

namespace myNamespace
{
    public class DailyTraceListener : TraceListener
    {
        private string _LogFileLocation = "";
        private DateTime _CurrentDate;
        StreamWriter _TraceWriter;

        public DailyTraceListener(string FileName)
        {
            _LogFileLocation = FileName;
            _TraceWriter = new StreamWriter(GenerateFileName(), true);
        }

        public override void Write(string message)
        {
            CheckRollover();
            _TraceWriter.Write(message);
        }

        public override void Write(string message, string category)
        {
            CheckRollover();
            _TraceWriter.Write(category + " " + message);
        }


        public override void WriteLine(string message)
        {
            CheckRollover();
            StringBuilder sb = new StringBuilder();
            sb.Append(DateTime.Now);
            sb.Append("##");
            sb.Append(Process.GetCurrentProcess().Id);
            sb.Append("##");
            sb.Append(AppDomain.GetCurrentThreadId());
            sb.Append("##");
            sb.Append(message);
            _TraceWriter.WriteLine(sb.ToString());
        }

        public override void WriteLine(string message, string category)
        {
            CheckRollover();
            StringBuilder sb = new StringBuilder();
            sb.Append(DateTime.Now);
            sb.Append("##");
            sb.Append(Process.GetCurrentProcess().Id);
            sb.Append("##");
            sb.Append(AppDomain.GetCurrentThreadId());
            sb.Append("##");
            sb.Append(category);
            sb.Append("##");
            sb.Append(message);
            _TraceWriter.WriteLine(sb.ToString());
        }

        private string GenerateFileName()
        {
            _CurrentDate = DateTime.Today;
            return Path.Combine(Path.GetDirectoryName(_LogFileLocation), Path.GetFileNameWithoutExtension(_LogFileLocation) + "_" + _CurrentDate.ToString("yyyyMMdd") + Path.GetExtension(_LogFileLocation));
        }

        private void CheckRollover()
        {
            if (_CurrentDate.CompareTo(DateTime.Today) != 0)
            {
                _TraceWriter.Close();
                _TraceWriter = new StreamWriter(GenerateFileName(),true);
            }
        }

        public override void Flush()
        {
            lock(this)
            {
                if (_TraceWriter != null)
                {
                    _TraceWriter.Flush();
                }
            }
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                _TraceWriter.Close();
            }
        }
    }
}

You can configure this by amending the App.Config file:

<system.diagnostics>
    <trace autoflush="true" indentsize="4">
        <listeners>
           <add name="myListener"  type="myNamespace.DailyTraceListener" initializeData="e:\logfiles\mylogfile.log" />
        </listeners>
    </trace>
</system.diagnostics>

So on the day of this submission this would create a file in e:\logfiles called mylogfile_20060726.log.