C#, Timer, Stopwatch, 精確計時器

stopwatch.sample.cs

/// 精確計時器
/// ref→[Stopwatch 類別](https://docs.microsoft.com/zh-tw/dotnet/api/system.diagnostics.stopwatch?view=net-6.0)

using System;
using System.Diagnostics;
using System.Threading;
class Program
{
    static void Main(string[] args)
    {
        Stopwatch stopWatch = new Stopwatch();
        stopWatch.Start();
        Thread.Sleep(10000);
        stopWatch.Stop();
        // Get the elapsed time as a TimeSpan value.
        TimeSpan ts = stopWatch.Elapsed;

        // Format and display the TimeSpan value.
        string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}",
            ts.Hours, ts.Minutes, ts.Seconds,
            ts.Milliseconds / 10);
        Console.WriteLine("RunTime " + elapsedTime);
    }
}

thread_timer_sample.cs

///
/// ref→[System.Thread.Timer](https://msdn.microsoft.com/zh-tw/library/system.threading.timer.aspx)
/// 當 timer 觸發時，以新的thread執行，為多執行緒。適合沒有UI的狀況。
///
/// .Net Framework 提供三種timer：
/// * System.Timers.Timer
/// * System.Threading.Timer
/// * System.Windows.Forms.Timer
/// 在此文章有討論[執行緒定時器](https://dotblogs.com.tw/yc421206/2011/01/30/21141)
///
/// 此例應用於 windows service
///
using System;
using System.Diagnostics;
using System.ServiceProcess;
using System.Threading;

namespace MyWindowsService
{
    public partial class MainService : ServiceBase
    {
        private System.Threading.Timer _timer = null;
        private readonly object _thisLock = new object(); // used to lock for synchronization
        private readonly object _timerLock = new object(); 

        public MainService()
        {
            InitializeComponent();
        }

        protected override void OnStart(string[] args)
        {
            Debug.WriteLine("OnStart");
            MyState state = new MyState();
            _timer = new System.Threading.Timer(MyTimerCallback, state, 1000, 1000);
        }

        protected override void OnStop()
        {
            Debug.WriteLine("OnStop");
            _timer.Dispose();
        }

        /// <summary>
        /// TimerCallback, This method is called by the timer delegate.
        /// </summary>
        public void MyTimerCallback(Object stateInfo)
        {
            lock(_timerLock) // 若有同步需求就需lock。
            {
                MyState state = (MyState)stateInfo;
                state.steps++;
                Debug.WriteLine("{0} {1:HH:mm:ss} {2}", "MyTimerCallback", DateTime.Now, state.steps);

                // 模擬執行時間差異性：模數為４時模擬跑３秒才完成，否則立即完成。
                if(state.steps % 4 == 0)
                    Thread.Sleep(3000);

                Debug.WriteLine("{0} {1:HH:mm:ss} {2}", "Sleep", DateTime.Now, state.steps);
            }
        }
    }

    internal class MyState
    {
        public int steps = 0;
    }
}