熱點推薦:
您现在的位置: 電腦知識網 >> 編程 >> .NET編程 >> 正文

提供一個獲取高精度時間類

2013-11-13 10:09:13  來源: .NET編程 

  如果你覺得用 DotNet 自帶的 DateTime 獲取的時間精度不夠解決的方法是通過調用 QueryPerformanceFrequency 和 QueryPerformanceCounter這兩個API來實現

     /// <summary>
/// 獲取時間的精度
/// </summary>
/// <param name=PerformanceFrequency></param>
/// <returns></returns>
        [SuppressUnmanagedCodeSecurity]
[DllImport(kernel)]
static private extern bool QueryPerformanceFrequency(ref long PerformanceFrequency);
/// <summary>
/// 獲取時間計數
/// </summary>
/// <param name=PerformanceCount></param>
/// <returns></returns>
        [SuppressUnmanagedCodeSecurity]
[DllImport(kernel)]
static private extern bool QueryPerformanceCounter(ref long PerformanceCount);

  下面是完整的封裝代碼

    /// <summary>
/// 定義一個高精度的時間類
/// </summary>
    public class Timer
{
#region private members
private long ticksPerSecond = ;
private long elapsedTime = ;
private long baseTime = ;
#endregion
#region windows API
/// <summary>
/// 獲取時間的精度
/// </summary>
/// <param name=PerformanceFrequency></param>
/// <returns></returns>
        [SuppressUnmanagedCodeSecurity]
[DllImport(kernel)]
static private extern bool QueryPerformanceFrequency(ref long PerformanceFrequency);
/// <summary>
/// 獲取時間計數
/// </summary>
/// <param name=PerformanceCount></param>
/// <returns></returns>
        [SuppressUnmanagedCodeSecurity]
[DllImport(kernel)]
static private extern bool QueryPerformanceCounter(ref long PerformanceCount);
#endregion
#region constructors
/// <summary>
/// new
/// </summary>
        public Timer()
{
// Use QueryPerformanceFrequency to get frequency of the timer
            if (!QueryPerformanceFrequency(ref ticksPerSecond))
throw new ApplicationException(Timer: Performance Frequency Unavailable);
Reset();
}
#endregion
#region public methods
/// <summary>
/// 重置時間相關計數器
/// </summary>
        public void Reset()
{
long time = ;
QueryPerformanceCounter(ref time);
baseTime = time;
elapsedTime = ;
}
/// <summary>
/// 獲取當前與最近一次 reset 時間差
/// </summary>
/// <returns>The time since last reset</returns>
        public double GetTime()
{
long time = ;
QueryPerformanceCounter(ref time);
return (double)(time baseTime) / (double)ticksPerSecond;
}
/// <summary>
/// 獲取當前系統的時間 ticks 數
/// </summary>
/// <returns>The current time in seconds</returns>
        public double GetAbsoluteTime()
{
long time = ;
QueryPerformanceCounter(ref time);
return (double)time / (double)ticksPerSecond;
}
/// <summary>
/// 獲取此次與上次調用此方法的兩次時間差
/// </summary>
/// <returns>The number of seconds since last call of this function</returns>
        public double GetElapsedTime()
{
long time = ;
QueryPerformanceCounter(ref time);
double absoluteTime = (double)(time elapsedTime) / (double)ticksPerSecond;
elapsedTime = time;
return absoluteTime;
}
#endregion
}
調用代碼
Timer t = new Timer();
tGetAbsoluteTime();
tGetElapsedTime();
tReset();
tGetTime();


From:http://tw.wingwit.com/Article/program/net/201311/12714.html
    推薦文章
    Copyright © 2005-2013 電腦知識網 Computer Knowledge   All rights reserved.