void CCERecordDlg::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar) 
{
if (IDC_SLIDER_PLAY == pScrollBar->GetDlgCtrlID())
{
CSliderCtrl* pPlay = (CSliderCtrl*)GetDlgItem(IDC_SLIDER_PLAY);
if (pPlay)
{
TRACE(_T("Play Volume %d\n"), pPlay->GetPos());
waveOutSetVolume(hWaveOut, (DWORD)pPlay->GetPos());
}
}

CDialog::OnHScroll(nSBCode, nPos, pScrollBar);
}