C# 創(chuàng)建高精度定時(shí)器的示例

更新時(shí)間：2021年02月27日 15:31:07 作者：Hello——尋夢(mèng)者！

這篇文章主要介紹了C# 創(chuàng)建高精度定時(shí)器的示例，幫助大家更好的理解和學(xué)習(xí)使用c#,感興趣的朋友可以了解下

背景

我們知道在.NET Framework中存在四種常用的定時(shí)器，他們分別是：

1 兩個(gè)是通用的多線程定時(shí)器：

System.Threading.Timer
System.Timers.Timer

2 兩個(gè)是專(zhuān)用的單線程定時(shí)器

System.Windows.Forms.Timer （Windows Forms 的定時(shí)器）
System.Windows.Threading.DispatcherTimer （WPF 的定時(shí)器）

通常他們的精度只能維持在10-20ms之間，這個(gè)和操作系統(tǒng)相關(guān)，所以我們?cè)诤芏鄨?chǎng)景下面這個(gè)是不能夠達(dá)到我們精度的要求的，如果要實(shí)現(xiàn)這一需求我們?cè)撛趺崔k，當(dāng)然也有很多辦法，今天主要介紹一種Stopwatch來(lái)實(shí)現(xiàn)的方式，網(wǎng)上有很多采用Win32 Dll的API這個(gè)當(dāng)然是可以的，這篇文章的重點(diǎn)不是去討論這個(gè)，關(guān)于使用Win32 API的方式可以參考這里。

實(shí)現(xiàn)

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
 
namespace Pangea.Common.Utility
{
    /// <summary>
    /// .Net Stopwatch對(duì)高精度定時(shí)器作了很好的包裝
    /// DeviceTimer內(nèi)部采用Stopwatch類(lèi)實(shí)現(xiàn)高精度定時(shí)操作
    /// </summary>
    public sealed class DeviceTimer
    {
#if USE_CPU_COUNTING
        //引入高性能計(jì)數(shù)器API，通過(guò)對(duì)CPU計(jì)數(shù)完成計(jì)時(shí)
        [DllImport("Kernel32.dll")]
        private static extern bool QueryPerformanceCounter(out long lpPerformanceCount);
 
        //獲取當(dāng)前CPU的工作頻率
        [DllImport("Kernel32.dll")]
        private static extern bool QueryPerformanceFrequency(out long lpFrequency);
#else
        /// <summary>
        /// 獲取TickCount64計(jì)數(shù)
        /// </summary>
        /// <returns></returns>
        //[DllImport("kernel32.dll")]
        //public static extern long GetTickCount64();
#endif
        private enum DeviceTimerState
        {
            TM_ST_IDLE = 0,
            TM_ST_BUSY = 1,
            TM_ST_TIMEOUT = 2,
        }
 
        /// <summary>
        /// Stopwatch object
        /// </summary>
        Stopwatch _stopWatch = new Stopwatch();
 
        /// <summary>
        /// 定時(shí)器內(nèi)部狀態(tài)
        /// </summary>
        DeviceTimerState _state;
 
        /// <summary>
        /// 定時(shí)器開(kāi)始計(jì)時(shí)時(shí)刻的相對(duì)時(shí)間點(diǎn)
        /// </summary>
        long _startTime;
 
        /// <summary>
        /// 定時(shí)器超時(shí)時(shí)刻的相對(duì)時(shí)間點(diǎn)
        /// </summary>
        long _timeOut;
 
#if USE_CPU_COUNTING
 
        /// <summary>
        /// CPU運(yùn)行的時(shí)鐘頻率
        /// </summary>
        double _freq;
#endif
 
        /// <summary>
        /// 定時(shí)時(shí)間（單位：ms）
        /// </summary>
        double _duration;
 
        /// <summary>
        /// class constructure
        /// </summary>
        public DeviceTimer()
        {
#if USE_CPU_COUNTING
            long freq;
            if (QueryPerformanceFrequency(out freq) == false)
                throw new Exception("本計(jì)算機(jī)不支持高性能計(jì)數(shù)器");
            //得到每1ms的CPU計(jì)時(shí)TickCount數(shù)目
            _freq = (double)freq / 1000.0;
            QueryPerformanceCounter(out _startTime);
#else
            _stopWatch.Start();
            _startTime = 0;
#endif
            SetState(DeviceTimerState.TM_ST_IDLE);
            _timeOut = _startTime;
            _duration = 0;
        }
 
        /// <summary>
        /// 內(nèi)部調(diào)用：設(shè)置定時(shí)器當(dāng)前狀態(tài)
        /// </summary>
        /// <param name="state"></param>
        private void SetState(DeviceTimerState state)
        {
            _state = state;
        }
 
        /// <summary>
        /// 內(nèi)部調(diào)用：返回定時(shí)器當(dāng)前狀態(tài)
        /// </summary>
        /// <returns></returns>
        private DeviceTimerState GetState()
        {
            return _state;
        }
 
        /// <summary>
        /// 定時(shí)器開(kāi)始計(jì)時(shí)到現(xiàn)在已流逝的時(shí)間（單位：毫秒）
        /// </summary>
        /// <returns></returns>
        public double GetElapseTime()
        {
            long curCount;
#if USE_CPU_COUNTING
            QueryPerformanceCounter(out curCount);
            return (double)(curCount - _startTime) / (double)_freq;
#else
            curCount = _stopWatch.ElapsedMilliseconds;
            return curCount - _startTime;
#endif
        }
 
        /// <summary>
        /// 獲取定時(shí)總時(shí)間
        /// </summary>
        /// <returns></returns>
        public double GetTotalTime()
        {
            return _duration;
        }
 
        /// <summary>
        /// 停止計(jì)時(shí)器計(jì)時(shí)
        /// </summary>
        public void Stop()
        {
            SetState(DeviceTimerState.TM_ST_IDLE);
#if USE_CPU_COUNTING
            QueryPerformanceCounter(out _startTime);
#else
            _startTime = _stopWatch.ElapsedMilliseconds;
#endif
            _timeOut = _startTime;
            _duration = 0;
        }
 
        /// <summary>
        /// 啟動(dòng)定時(shí)器
        /// </summary>
        /// <param name="delay_ms">定時(shí)時(shí)間（單位：毫秒）</param>
        public void Start(double delay_ms)
        {
#if USE_CPU_COUNTING
            QueryPerformanceCounter(out _startTime);
            _timeOut = Convert.ToInt64(_startTime + delay_ms * _freq);
#else
            _startTime = _stopWatch.ElapsedMilliseconds;
            _timeOut = Convert.ToInt64(_startTime + delay_ms);
#endif
            SetState(DeviceTimerState.TM_ST_BUSY);
            _duration = delay_ms;
        }
 
        /// <summary>
        /// 重新開(kāi)始定時(shí)器
        /// 開(kāi)始的計(jì)時(shí)時(shí)間以上一次Start的時(shí)間為準(zhǔn)
        /// </summary>
        /// <param name="delay_ms">定時(shí)時(shí)間（單位：毫秒）</param>
        public void Restart(double delay_ms)
        {
#if USE_CPU_COUNTING
            _timeOut = Convert.ToInt64(_startTime + delay_ms * _freq);
#else
            _timeOut = Convert.ToInt64(_startTime + delay_ms);
#endif
            SetState(DeviceTimerState.TM_ST_BUSY);
            _duration = delay_ms;
        }
 
        /// <summary>
        /// 返回定時(shí)器是否超時(shí)
        /// </summary>
        /// <returns></returns>
        public bool IsTimeout()
        {
            if (_state == DeviceTimerState.TM_ST_IDLE)
            {
                //System.Diagnostics.Debug.WriteLine("Warning: Misuage of the device timer. You must start it first before you can use it.");
                //System.Diagnostics.Debug.Assert(false, "Warning: Misuage of the device timer. You must start it first before you can use it.");
            }
            long curCount;
#if USE_CPU_COUNTING
            QueryPerformanceCounter(out curCount);
#else
            curCount = _stopWatch.ElapsedMilliseconds;
#endif
            if (_state == DeviceTimerState.TM_ST_BUSY && (curCount >= _timeOut))
            {
                SetState(DeviceTimerState.TM_ST_TIMEOUT);
                return true;
            }
            else if (_state == DeviceTimerState.TM_ST_TIMEOUT)
            {
                return true;
            }
            return false;
        }
 
        /// <summary>
        /// 定時(shí)器是否在工作中
        /// </summary>
        /// <returns></returns>
        public bool IsIdle()
        {
            return (_state == DeviceTimerState.TM_ST_IDLE);
        }
    }
}

　　這個(gè)里面我們?cè)贒eviceTimer中定義了一個(gè)私有的_stopWatch 對(duì)象并且在構(gòu)造函數(shù)中就啟動(dòng)了這個(gè)Stopwatch,所以我們?cè)谑褂玫臅r(shí)候是通過(guò)先創(chuàng)建一個(gè)DeveiceTimer的對(duì)象然后我們?cè)僬{(diào)用內(nèi)部的Start方法，當(dāng)然在調(diào)用這個(gè)方法的時(shí)候我們需要傳入一個(gè)定時(shí)時(shí)間，然后不斷檢測(cè)IsTimeout方法看是否到達(dá)定時(shí)時(shí)間，從而達(dá)到類(lèi)似于定時(shí)時(shí)間到的效果，另外GetElapseTime()方法能夠獲取從調(diào)用Start方法開(kāi)始到現(xiàn)在的時(shí)間，另外我們還在其中定義了幾個(gè)枚舉值用來(lái)表示當(dāng)前DeviceTimer的狀態(tài)用于做一些狀態(tài)的校驗(yàn)，具體數(shù)值如下。

private enum DeviceTimerState
{
    TM_ST_IDLE = 0,
    TM_ST_BUSY = 1,
    TM_ST_TIMEOUT = 2,
}

　　這里還有最后一個(gè)問(wèn)題就是循環(huán)調(diào)用的問(wèn)題，這個(gè)其實(shí)也是非常簡(jiǎn)單就在一個(gè)While循環(huán)中不斷進(jìn)行調(diào)用，當(dāng)然下面的代碼可以有很多內(nèi)容供我們?nèi)グl(fā)揮的，這個(gè)可以根據(jù)自己的需要進(jìn)行修改。

using System;
using System.Threading.Tasks;
 
namespace DeviceTimerConsoleApp
{
    class Program
    {
        private static bool flag = true;
        static void Main(string[] args)
        {
            Task.Factory.StartNew(() =>
            {
                var deviceTimer = new DeviceTimer();
                deviceTimer.Start(5);
 
                while (flag)
                {
                    if (deviceTimer.IsTimeout())
                    {
                        Console.WriteLine($"定時(shí)時(shí)間已到，距離開(kāi)始執(zhí)行已過(guò)去：{deviceTimer.GetElapseTime()}ms");
 
                        deviceTimer.Start(5);
                    }
                }
            });
            Console.ReadKey();
        }
    }
     
}

　　我們來(lái)看看定時(shí)器的效果