VC：大型WAV文件的播放(3)

　　DWORD CWave::CloseDevice()
　　{
　　 DWORD dwResult=0;

//close if currently open
if(m_nDeviceID)
{

//close the MCI device
dwResult=mciSendCommand(m_nDeviceID,MCI_CLOSE,NULL,NULL);

//display error message if failed
if(dwResult)
DisplayErrorMsg(dwResult);

//set identifier to close state
else
m_nDeviceID=0;
}

//return result of MCI operation
return dwResult;
　　}

　　DWORD CWave::Play(CWnd* pWnd,LPCSTR pFileName)
　　{
MCI_OPEN_PARMS mciOpenParms;
//initialize structure
memset(&mciOpenParms,0,sizeof(MCI_OPEN_PARMS));

//set the WAV file name to be played
mciOpenParms.lpstrElementName=pFileName;

//first open the device
DWORD dwResult=mciSendCommand(m_nDeviceID,MCI_OPEN,
MCI_OPEN_ELEMENT,(DWORD)(LPVOID)&mciOpenParms);

//display error message if failed
if(dwResult)
DisplayErrorMsg(dwResult);

//if successful,instruct the device to play the WAV file
else
{

//save element indentifier
m_nElementID=mciOpenParms.wDeviceID;

MCI_PLAY_PARMS mciPlayParms;

//set the window that will receive notification message
mciPlayParms.dwCallback=(DWORD)pWnd->m_hWnd;

//instruct device to play file
dwResult=mciSendCommand(m_nElementID,MCI_PLAY,
MCI_NOTIFY,(DWORD)(LPVOID)&mciPlayParms);

//display error and close element if failed
if(dwResult)
{
DisplayErrorMsg(dwResult);
Stop();
}
}