【原创】利用Windows系统日志统计员工每天上下班考勤时间

利用Windows系统日志统计员工每天上下班考勤时间（命令行参数为统计月份）：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;

namespace ConsoleSysLogView
{
    class Program
    {
        static void Main(string[] args)
        {
            SystemLog log = new SystemLog();
            if (args.Length == 1)
            {
                int x = Convert.ToInt32(args[0]);
                log.PrintEventLog(x);
            }
            else
            {
                Console.WriteLine("Event count: " + log.Count);
                Console.WriteLine("QueryMessage: SysLogView.exe MonthNum");
            }

            if (Debugger.IsAttached) Console.ReadKey();
        }
    }

    public class SystemLog
    {
        private EventLogEntryCollection _eventCollection;
        private EventLog _systemEvent;

        public SystemLog()
        {
            _systemEvent = new EventLog();
            _systemEvent.Log = "System";
            _eventCollection = _systemEvent.Entries;
        }

        public void PrintEventLog(int month)
        {
            DateTime dateFrom = new DateTime(DateTime.Now.Year, month, 1);
            DateTime dateTo = dateFrom.AddMonths(1);

            DateTime dt = dateFrom;
            while (dt < dateTo)
            {
                IList<EventLogEntry> list = Events.Where(a => a.TimeGenerated.Date == dt.Date).OrderBy(a => a.TimeGenerated).ToList();
                if (list.Count > 0)
                {
                    Console.WriteLine();
                    Console.WriteLine(GetLogEntryText(list[0]));
                    if (list.Count > 1)
                    {
                        int l = list.Count - 1;
                        Console.WriteLine(GetLogEntryText(list[l]));
                    }
                }

                dt = dt.AddDays(1);
            }
        }

        private string GetLogEntryText(EventLogEntry entry)
        {
            return string.Format("{0} {1:yyyy-MM-dd HH:mm} 来源：{2} 事件ID：{3}", entry.EntryType, entry.TimeGenerated.ToString("yyyy-MM-dd HH:mm"), entry.Source, entry.InstanceId);
        }

        private IList<EventLogEntry> _events;
        public IList<EventLogEntry> Events
        {
            get
            {
                if (_events == null)
                {
                    _events = new List<EventLogEntry>();

                    for (int i = 0; i < _eventCollection.Count; i++)
                    {
                        EventLogEntry entry = _eventCollection[i];
                        _events.Add(entry);
                        if (i % 1000 == 0) Console.Write(".");
                    }
                }

                return _events;
            }
        }

        public int Count
        {
            get { return Events.Count; }
        }

    }
}