高精度多媒體時鐘應用類

<pre class="cpp" name="code">/////////////////////////////////////////////
//High-Resolution Timer
//多媒體高精度時鐘應用類
/////////////////////////////////////////////

#include <MMSYSTEM.H>
#pragma comment(lib, "WINMM.LIB")

class CHighResolutionTimer
{
    typedef void (*TIMERCALLBACK)(DWORD);

private:
    DWORD m_dwUser;
    MMRESULT m_nIDTimer;
    UINT m_uDelay;
    TIMERCALLBACK m_pfnCallback;

    void KillTimer()
    {
        if(m_nIDTimer != NULL)
        {
            timeKillEvent(m_nIDTimer);
            m_nIDTimer = NULL;
        }
    }

public:
    CHighResolutionTimer()
    {
        m_nIDTimer = NULL;
        m_uDelay = 0;
        m_pfnCallback = 0;
    }

    virtual ~CHighResolutionTimer()
    {
        KillTimer();
    }

    static void CALLBACK TimeProc(UINT uID,UINT uMsg,DWORD dwUser,DWORD dw1, DWORD dw2)
    {
        // dwUser contains ptr to Timer object
        CHighResolutionTimer * ptimer = (CHighResolutionTimer *) dwUser;
        // Call user-specified callback and pass back user specified data
        (ptimer->m_pfnCallback) (ptimer->m_dwUser);
    }

    BOOL CreateTimer(DWORD dwUser,UINT uDelay,TIMERCALLBACK lpTimeProc)
    {
        ASSERT(dwUser);
        ASSERT(lpTimeProc);

        m_dwUser = dwUser;
        m_pfnCallback = lpTimeProc;
        BOOL ret = FALSE;
        KillTimer();
        m_nIDTimer = timeSetEvent (uDelay, 0, TimeProc, (DWORD)this, TIME_PERIODIC | TIME_CALLBACK_FUNCTION);

        if(m_nIDTimer != NULL)
            ret = TRUE;
        return(ret);
    }
};

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<pre class="csharp" name="code">//應用 .h

  CHighResolutionTimer mm_Timer;
  static void TimerCallback (DWORD dwUser);

//應用 .cpp
定時器回調
void CMy_TimerDlg::TimerCallback (DWORD dwUser)
{
    CMy_TimerDlg *pThis = (CMy_TimerDlg *)dwUser;

    //
    static long count = 0;
    CString str;
    str.Format("%d",count++);
    pThis->GetDlgItem(IDC_BUTTON1)->SetWindowText(str);
    Beep(1000,1);
}



//啓動2毫秒定時器
void CMy_TimerDlg::OnButton1()
{
    // TODO: Add your control notification handler code here
    //
    mm_Timer.CreateTimer((DWORD)this,2,TimerCallback);
}

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<p> </p>
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