请教调节音量问题

[yuanshengkj2009]

用Slider控件控制音量的代码我知道怎么实现了。现在我想让它修改为控制话筒音量，怎么修改？相关代码如下：

BOOL COnLine::OnInitDialog() 
{
    CDialog::OnInitDialog();

        if (this->amdInitialize())
    {
    
        // get the Control ID and the names
        if (this->amdGetMasterVolumeControl())
        {
        m_ctrlSlider.SetRange(m_dwMinimum, m_dwMaximum);
    
            DWORD dwVal = 0;
            if (this->amdGetMasterVolumeValue(dwVal))
            {
                m_ctrlSlider.SetPos(dwVal);
            }
            else
            {
                ASSERT(FALSE);
            }
        }
        else
        {
        
            m_ctrlSlider.EnableWindow(FALSE);
        }

        else
    {
        ASSERT(FALSE);
    }
    return TRUE;  // return TRUE unless you set the focus to a control
                  // EXCEPTION: OCX Property Pages should return FALSE
}
BOOL COnLine::amdGetMasterVolumeControl()
{
    if (m_hMixer == NULL)
    {
        return FALSE;
    }

    // get dwLineID
    MIXERLINE mxl;
    mxl.cbStruct = sizeof(MIXERLINE);
    mxl.dwComponentType = MIXERLINE_COMPONENTTYPE_DST_SPEAKERS;
    if (::mixerGetLineInfo(reinterpret_cast<HMIXEROBJ>(m_hMixer),
                           &mxl,
                           MIXER_OBJECTF_HMIXER |
                           MIXER_GETLINEINFOF_COMPONENTTYPE)
        != MMSYSERR_NOERROR)
    {
        return FALSE;
    }

    // get dwControlID
    MIXERCONTROL mxc;
    MIXERLINECONTROLS mxlc;
    mxlc.cbStruct = sizeof(MIXERLINECONTROLS);
    mxlc.dwLineID = mxl.dwLineID;
    mxlc.dwControlType = MIXERCONTROL_CONTROLTYPE_VOLUME;
    mxlc.cControls = 1;
    mxlc.cbmxctrl = sizeof(MIXERCONTROL);
    mxlc.pamxctrl = &mxc;
    if (::mixerGetLineControls(reinterpret_cast<HMIXEROBJ>(m_hMixer),
                               &mxlc,
                               MIXER_OBJECTF_HMIXER |
                               MIXER_GETLINECONTROLSF_ONEBYTYPE)
        != MMSYSERR_NOERROR)
    {
        return FALSE;
    }

    // store dwControlID
    m_strDstLineName = mxl.szName;
    m_strVolumeControlName = mxc.szName;
    m_dwMinimum = mxc.Bounds.dwMinimum;
    m_dwMaximum = mxc.Bounds.dwMaximum;
    m_dwVolumeControlID = mxc.dwControlID;

    return TRUE;
}
BOOL COnLine::amdGetMasterVolumeValue(DWORD &dwVal) const
{
    if (m_hMixer == NULL)
    {
        return FALSE;
    }

    MIXERCONTROLDETAILS_UNSIGNED mxcdVolume;
    MIXERCONTROLDETAILS mxcd;
    mxcd.cbStruct = sizeof(MIXERCONTROLDETAILS);
    mxcd.dwControlID = m_dwVolumeControlID;
    mxcd.cChannels = 1;
    mxcd.cMultipleItems = 0;
    mxcd.cbDetails = sizeof(MIXERCONTROLDETAILS_UNSIGNED);
    mxcd.paDetails = &mxcdVolume;
    if (::mixerGetControlDetails(reinterpret_cast<HMIXEROBJ>(m_hMixer),
                                 &mxcd,
                                 MIXER_OBJECTF_HMIXER |
                                 MIXER_GETCONTROLDETAILSF_VALUE)
        != MMSYSERR_NOERROR)
    {
        return FALSE;
    }
    
    dwVal = mxcdVolume.dwValue;

    return TRUE;
}

BOOL COnLine::amdSetMasterVolumeValue(DWORD dwVal) const
{
    if (m_hMixer == NULL)
    {
        return FALSE;
    }

    MIXERCONTROLDETAILS_UNSIGNED mxcdVolume = { dwVal };
    MIXERCONTROLDETAILS mxcd;
    mxcd.cbStruct = sizeof(MIXERCONTROLDETAILS);
    mxcd.dwControlID = m_dwVolumeControlID;
    mxcd.cChannels = 1;
    mxcd.cMultipleItems = 0;
    mxcd.cbDetails = sizeof(MIXERCONTROLDETAILS_UNSIGNED);
    mxcd.paDetails = &mxcdVolume;
    if (::mixerSetControlDetails(reinterpret_cast<HMIXEROBJ>(m_hMixer),
                                 &mxcd,
                                 MIXER_OBJECTF_HMIXER |
                                 MIXER_SETCONTROLDETAILSF_VALUE)
        != MMSYSERR_NOERROR)
    {
        return FALSE;
    }
    
    return TRUE;
}

[yuanshengkj2009]

BOOL COnLine::amdInitialize()
{
ASSERT(m_hMixer == NULL);

// get the number of mixer devices present in the system
m_nNumMixers = ::mixerGetNumDevs();

m_hMixer = NULL;
::ZeroMemory(&m_mxcaps, sizeof(MIXERCAPS));

m_strDstLineName.Empty();
m_strVolumeControlName.Empty();
m_dwMinimum = 0;
m_dwMaximum = 0;
m_dwVolumeControlID = 0;

// open the first mixer
// A "mapper" for audio mixer devices does not currently exist.
if (m_nNumMixers != 0)
{
if (::mixerOpen(&m_hMixer,
0,
reinterpret_cast<DWORD>(this->GetSafeHwnd()),
NULL,
MIXER_OBJECTF_MIXER | CALLBACK_WINDOW)
!= MMSYSERR_NOERROR)
{
return FALSE;
}

if (::mixerGetDevCaps(reinterpret_cast<UINT>(m_hMixer),
&m_mxcaps, sizeof(MIXERCAPS))
!= MMSYSERR_NOERROR)
{
return FALSE;
}
}

return TRUE;
}

BOOL COnLine::amdUninitialize()
{
BOOL bSucc = TRUE;

if (m_hMixer != NULL)
{
bSucc = (::mixerClose(m_hMixer) == MMSYSERR_NOERROR);
m_hMixer = NULL;
}

return bSucc;
}