// 헤더
virtual BOOL OnInitDialog();
afx_msg LRESULT HandleInitDialog(WPARAM, LPARAM);

// 소스
BEGIN_MESSAGE_MAP(Class, CPaneDialog)
    ...
    ON_MESSAGE(WM_INITDIALOG, HandleInitDialog)
END_MESSAGEMAP()

BOOL Class::OnInitDialog()
{
    UpdateData(FALSE);

    return TRUE;
}

LRESULT Class::HandleInitDialog(WPARAM wParam, LPARAM lParam)
{
    OnInitDialog();

    return CPaneDialog::HandleInitDialog(wParam, lParam);
}