【共享】WinCE 6.0中精确定时的实现

借用了网友关于win32平台精确定时的方法，将平台调用中的kernel32.dll换成coredll.dll即可。经测试，时间精度到ms以下

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace SmartDeviceProject3
{
public partial class MainForm : Form
{
public MainForm()
{
InitializeComponent();
}

private void MainForm_Paint( object sender, PaintEventArgs e)
{
int sum = 1 ;
HiPerfTimer pt = new HiPerfTimer(); // 创建新的 HiPerfTimer 对象
pt.Start(); // 启动计时器
for ( int i = 1 ; i < 100000 ; i ++ )
{
sum *= i;
}
pt.Stop(); // 停止计时器
MessageBox.Show(pt.Duration.ToString()); // 执行时间按2.35ms,SBC8100开发板
}
class HiPerfTimer
{
[DllImport( " coredll.dll " )]
private static extern bool QueryPerformanceCounter(
out long lpPerformanceCount);

[DllImport( " coredll.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 System.Exception( " High performance timer not supported " );
}
}

// 开始计时器
public void Start()
{
// 来让等待线程工作
System.Threading.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：毫秒)
public double Duration
{
get
{
return (( double )(stopTime - startTime) / ( double )freq) * 1000 ;
}
}
}
}