NMHDR nm;
nm.code = 123456; // 这里是消息的区别代码
nm.hwndFrom = m_hWnd;//这是控件的HWND句柄
nm.idFrom = GetDlgCtrlID();//这是得到的对话框的ID

CWnd* pWnd;
  pWnd = GetParent(); //得到父窗体 窗口
  if (pWnd != NULL)
  {
    pWnd->SendMessage(WM_NOTIFY, nm.idFrom, (LPARAM)&nm); //向父窗体发送消息
  }

BOOL CMyControlDlg::OnNotify(WPARAM wParam, LPARAM lParam, LRESULT* pResult)
{

  if ((UINT)wParam == IDC_CUSTOM2)
  {
    AfxMessageBox(_T("成功"));
  }
  return CDialogEx::OnNotify(wParam, lParam, pResult);
}