[求助] 为SerialPort增加WM_COMM_RXCHAR消息响应出错，求解答。

// Generated message map functions
//{{AFX_MSG(CSerialPortTestDlg)
afx_msg LONG OnComm(WPARAM ch, LPARAM port);  
//}}AFX_MSG

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
//{{AFX_MSG_MAP(CAboutDlg)
// No message handlers
ON_MESSAGE(WM_COMM_RXCHAR, OnComm)   
//}}AFX_MSG_MAP
END_MESSAGE_MAP()

LONG CSerialPortTestDlg::OnComm(WPARAM ch, LPARAM port)
{
m_strEditReceiveMsg += ch;
UpdateData(FALSE);
return 0;
}

D:\VC6.0\Work Program\MSComm\SerialPortTest\SerialPortTestDlg.cpp(56) : error C2065: 'OnComm' : undeclared identifier
D:\VC6.0\Work Program\MSComm\SerialPortTest\SerialPortTestDlg.cpp(56) : error C2440: 'type cast' : cannot convert from 'int *' to 'long (__thiscall CWnd::*)(unsigned int,long)'
        There is no context in which this conversion is possible