使用mciSendCommand循环播放音乐

方法一：最简单的方法

使用重复播放参数：MCI_DGV_PLAY_REPEAT

mciSendCommand(m_nDeviceID, MCI_PLAY, MCI_DGV_PLAY_REPEAT, (DWORD)&mciPlay))

需要头文件：

#include <Digitalv.h>
#include <MMSystem.h>
#pragma comment(lib , "winmm.lib")
。。。。。。

 MCIDEVICEID m_nDeviceID;
。。。。。。

void CMyDlg::OpenMciDeveci(void)
{
    DWORD dwResult = 0;

    MCI_OPEN_PARMS mciOpenParms;
    mciOpenParms.lpstrDeviceType = _T("sequencer");
    mciOpenParms.lpstrElementName = _T(SOUND_BACK);


    dwResult = mciSendCommand(NULL, 
        MCI_OPEN,
        MCI_OPEN_ELEMENT,
        (DWORD)&mciOpenParms);
   
    //save device identifier,will use eith other MCI commands
    m_nDeviceID = mciOpenParms.wDeviceID;
    if (dwResult != 0)
    {
       MessageBox(L"加载背景音乐失败！");
    }

}

void CMyDlg::PlayBackMusic(void)
{
    MCI_PLAY_PARMS mciPlay;
    if(mciSendCommand(m_nDeviceID, MCI_PLAY, MCI_DGV_PLAY_REPEAT, (DWORD)&mciPlay))
    {
        MessageBox(L"播放背景音乐失败！");
    }
}

方法二：通过响应MM_MCINOTIFY消息来重复播放声音。详情参考这里：http://www.vckbase.com/document/viewdoc/?id=633

我把他的代码改装了下。利用MCI_SEEK命令将播放位置重置到开头，然后再调用MCI_PLAY命令，即可从头开始播放。这样就省去了打开关闭文件时带来的额外开销。

///MCIPlayMusic.h 
/** 
* @file MCIPlayMusic.h 
* @author 游蓝海
* @mail you_lan_hai@foxmail.com
* @data 2011-11-30
* 说明：
* 改装自如《何播放大型 WAV 文件？》 
* 原作者：hermess
* http://www.vckbase.com/document/viewdoc/?id=633
*/
#pragma once

#include <MMSystem.h>

/**播放音乐类*/
class cMciPlayMusic
{
public:
    ///构造函数
    cMciPlayMusic();
    virtual ~cMciPlayMusic();

public:
    DWORD openDevice();
    DWORD closeDevice();
    DWORD play(CWnd *pParentWnd,LPCTSTR pFileName);
    DWORD stop();
    DWORD seekToStart();

    LPCTSTR getErrorMsg(DWORD dwError);
    
    MCIDEVICEID getDeviceID(void){ return m_nDeviceID; }
    MCIDEVICEID getElementID(void){ return m_nElementID; }

protected:
    MCIDEVICEID m_nDeviceID;
    MCIDEVICEID m_nElementID;
};

#include <stdafx.h>
#include "MCIPlayMusic.h"

cMciPlayMusic::cMciPlayMusic()
{
    m_nDeviceID=0;
    m_nElementID=0;
}

cMciPlayMusic::~cMciPlayMusic()
{
    if(m_nElementID != 0)
    {
        stop();
    }
    if(m_nDeviceID != 0)
    {
        closeDevice();
    }
}

DWORD cMciPlayMusic::openDevice()
{
    DWORD dwResult=0;

    if (m_nDeviceID == 0)
    {
        MCI_OPEN_PARMS mciOpenParms;
        ZeroMemory(&mciOpenParms, sizeof(mciOpenParms));

        //mciOpenParms.lpstrDeviceType = (LPCTSTR)MCI_DEVTYPE_WAVEFORM_AUDIO;
        mciOpenParms.lpstrDeviceType = (LPCTSTR)MCI_DEVTYPE_SEQUENCER;
        
        //open the wave device
        dwResult = mciSendCommand(NULL,
            MCI_OPEN,
            MCI_OPEN_TYPE|MCI_OPEN_TYPE_ID|MCI_WAIT,
            (DWORD)(LPVOID)&mciOpenParms);

        //save device identifier,will use eith other MCI commands
        m_nDeviceID = mciOpenParms.wDeviceID;

    }
    //return result of MCI operation
    return dwResult;
}

DWORD cMciPlayMusic::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)
        {
            m_nDeviceID=0;
        }
    }

    //return result of MCI operation
    return dwResult;
}

DWORD cMciPlayMusic::play(CWnd* pWnd,LPCTSTR pFileName)
{
    if (m_nElementID == 0)
    {
        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);

        if (dwResult != 0)
        {
            return dwResult;
        }
        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
    DWORD dwResult=mciSendCommand(m_nElementID,MCI_PLAY,
        MCI_NOTIFY,(DWORD)(LPVOID)&mciPlayParms);

    //display error and close element if failed
    if(dwResult != 0)//失败
    {
        stop();
    }

    //return result of MCI operation
    return dwResult;
}


DWORD cMciPlayMusic::stop()
{
    DWORD dwResult=0;

    //close if element is currently open
    if(m_nElementID != 0)
    {
        dwResult=mciSendCommand(m_nElementID,MCI_CLOSE,NULL,NULL);

        //display error message if failed
        if(dwResult == 0)
        {
            m_nElementID=0;
        }
    }
    return dwResult;
}

DWORD cMciPlayMusic::seekToStart()
{
    DWORD dwResult=0;

    //close if element is currently open
    if(m_nElementID != 0)
    {
        MCI_SEEK_PARMS seekParam;
        ZeroMemory(&seekParam, sizeof(seekParam));
        dwResult=mciSendCommand(m_nElementID,
            MCI_SEEK,
            MCI_SEEK_TO_START,
            (DWORD)&seekParam);
    }
    return dwResult;
}

LPCTSTR cMciPlayMusic::getErrorMsg(DWORD dwError)
{
    //character string that contains error message
    static TCHAR szErrorMsg[MAXERRORLENGTH];

    //check if there was an error
    if(dwError)
    {
        //retrieve string associated error message
        if(!mciGetErrorString(dwError,szErrorMsg,sizeof(szErrorMsg)))
        {
            lstrcpy(szErrorMsg,_T("未知错误。"));
        }
    }
    else
    {
        lstrcpy(szErrorMsg, _T("没有错误。"));
    }
    return szErrorMsg;
}

给窗口添加响应消息： ON_MESSAGE(MM_MCINOTIFY, &CMyDlg::OnMCINotify)

LRESULT CMyDlg::OnMCINotify(WPARAM wParam, LPARAM lParam)
{
    if (wParam == MCI_NOTIFY_SUCCESSFUL )
    {
        PlayBackMusic();
    }
    return 0;
}


void CMyDlg::OpenMciDeveci(void)
{
    DWORD dwResult = 0;

    dwResult = m_mciMusic.openDevice();
    if(0 != dwResult)
    {
        MessageBox(m_mciMusic.getErrorMsg(dwResult));
    }

}


void CMyLLKDlg::PlayBackMusic(void)
{

     m_mciMusic.seekToStart();
    //m_mciMusic.stop();
    DWORD dwResult = m_mciMusic.play(this, _T(“your_music.mp3”));
    if (dwResult != 0)
    {
        MessageBox(m_mciMusic.getErrorMsg(dwResult));
    }

}

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使用mciSendCommand循环播放音乐

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