イベントログにログ出力する共通クラス

LogHelper.cs

using System;
using System.Diagnostics;

namespace LogSample.Service
{
    public class LogHelper
    {
        private static readonly string _SOURCE_NAME = "Application";
        private static string _MESSAGE_FORMAT = "OccurrTime:{0};Message:{1}";
        private static EventLog _log;
        private static LogHelper _eventLogInstance;

        public static LogHelper Instance
        {
            get
            {
                if (_eventLogInstance == null)
                {
                    //if (!EventLog.SourceExists(_SOURCE_NAME))
                    //{
                    //    EventLog.CreateEventSource(_SOURCE_NAME, "");
                    //}
                    _eventLogInstance = new LogHelper();
                }
                return _eventLogInstance;
            }
        }

        public LogHelper()
        {
            _log = new EventLog();
            _log.Source = _SOURCE_NAME;
        }

        public void WriteError(string message)
        {
            _log.WriteEntry(String.Format("Error: " + _MESSAGE_FORMAT, DateTime.Now, message)
                , EventLogEntryType.Error);//, 2);
        }

        public void WriteWarn(string message)
        {
            _log.WriteEntry(String.Format("Warn: " + _MESSAGE_FORMAT, DateTime.Now, message)
                , EventLogEntryType.Warning);//, 3);
        }

        public void WriteInfo(string message)
        {
            _log.WriteEntry(String.Format("Info: " + _MESSAGE_FORMAT, DateTime.Now, message)
                , EventLogEntryType.Information);//, 4);
        }

    }
}

権限の問題が出てきそうなので現段階ではソース名はApplicationにしておく