MFC,多媒体定时器使用，提示异常

MFC,多媒体定时器使用，提示错误
class CDlg
{
MMRESULT timeSetEvent(UINT uDelay, UINT uResolution, LPTIMECALLBACK lpTimeProc, WORD dwUser, UINT fuEvent);
static void CALLBACK TimerCallBack(UINT uTimerID, UINT uMsg, DWORD dwUser, DWORD dw1, DWORD dw2);
int TimerID;
}；

TimerID=timeSetEvent(48,1,&TimerCallBack,(DWORD)this,1);

void CALLBACK CDlg::TimerCallBack(UINT uTimerID, UINT uMsg, DWORD dwUser, DWORD dw1, DWORD dw2)
{
  CDlg_UDP * pThis=(CDlg_UDP*)dwUser;//由this指针获得实例的指针
  pThis->OnTimer(1);//这儿直接调用的Timer消息处理中的OnTimer函数
}

下面提示错误：
HDRT_UDP.obj : error LNK2001: unresolved external symbol "public: unsigned int __thiscall CHDRT_UDP::timeSetEvent(unsigned int,unsigned int,void (__stdcall*)(unsigned int,unsigned int,unsigned long,unsigned long,unsigned long),unsigned short,unsigne
d int)" (?timeSetEvent@CHDRT_UDP@@QAEIIIP6GXIIKKK@ZGI@Z)
HDRT_UDP.obj : error LNK2001: unresolved external symbol __imp__timeKillEvent@4
Debug/HDRT_DQ.exe : fatal error LNK1120: 2 unresolved externals

这是怎么回事啊？请高手指点

------解决方案--------------------
class CDlg
{
MMRESULT timeSetEvent(UINT uDelay, UINT uResolution, LPTIMECALLBACK lpTimeProc, WORD dwUser, UINT fuEvent);//API timeSetEvent已经存在
static void CALLBACK TimerCallBack(UINT uTimerID, UINT uMsg, DWORD dwUser, DWORD dw1, DWORD dw2);
int TimerID;
}；

TimerID=timeSetEvent(48,1,&TimerCallBack,(DWORD)this,1);