using System;
using System.Runtime.InteropServices;
using System.ComponentModel;
using System.Threading;

namespace Win32
{
    internal class HiPerfTimer
    {
        [DllImport("Kernel32.dll")]
        private static extern bool QueryPerformanceCounter(
            out long lpPerformanceCount);

        [DllImport("Kernel32.dll")]
        private static extern bool QueryPerformanceFrequency(
            out long lpFrequency);

        private long startTime, stopTime;
        private long freq;

        // 构造函数
        public HiPerfTimer()
        {
            startTime = 0;
            stopTime  = 0;

            if (QueryPerformanceFrequency(out freq) == false)
            {
                // 不支持高性能计数器
                throw new Win32Exception();
            }
        }

        // 开始计时器
        public void Start()
        {
            // 来让等待线程工作
            Thread.Sleep(0);

            QueryPerformanceCounter(out startTime);
        }

        // 停止计时器
        public void Stop()
        {
            QueryPerformanceCounter(out stopTime);
        }

        // 返回计时器经过时间(单位：秒)
        public double Duration
        {
            get
            {
                return (double)(stopTime - startTime) / (double) freq;
            }
        }
    }
}

HiPerfTimer pt = new HiPerfTimer();     // 创建新的 HiPerfTimer 对象
pt.Start();                             // 启动计时器
Console.WriteLine("Test\n");            // 需要计时的代码
pt.Stop();                              // 停止计时器
Console.WriteLine("Duration: {0} sec\n", 
     pt.Duration); // 打印需要计时部分代码的用时