//首先做好自动更新宏
ON_UPDATE_COMMAND_UI_RANGE(ID_POPUPMENU_FIRST, ID_POPUPMENU_LAST, OnUpdatePopupMenuCmd)
//再声明更新消息函数
afx_msg void OnUpdatePopupMenuCmd(CCmdUI* pCmdUI);
//再做好函数
void CYourView::OnUpdatePopupMenuCmd(CCmdUI* pCmdUI)
{
  BOOL bEnable = FALSE;
  switch (pCmdUI->m_nID)
  {
    case ID_POPUPMENU_FIRST:
      if (....)
      {
        bEnable = TRUE;
      }
      break;
    case //........
    case ID_POPUPMENU_LAST:
      if (....)
      {
        bEnable = TRUE;
      }
      break;
    }
    pCmdUI->Enable(bEnable);
}
//在WM_CONTEXTMENU消息中做好弹出代码,或把代码放到WM_RBUTTONUP消息中
void CYourView::OnContextMenu(CWnd* pWnd, CPoint point)
{
  HMENU hMenu = ::LoadMenu(AfxGetApp()->m_hInstance, MAKEINTRESOURCE(IDR_POPUP));//弹出菜单资源
  HMENU hPopup = GetSubMenu(hMenu, 0);//第0个子菜单
  POINT pt = {point.x, point.y};
  ::ClientToScreen(m_hWnd, &pt);
  ::TrackPopupMenu(hPopup, TPM_LEFTALIGN | TPM_RIGHTBUTTON | TPM_VERTICAL, pt.x, pt.y, 0, m_hWnd, NULL);//弹出它
}

//添加WM_INITMENUPOPUP消息响应函数
void CYourView::OnInitMenuPopup(CMenu* pPopupMenu, UINT nIndex, BOOL bSysMenu)
{
  CScrollView::OnInitMenuPopup(pPopupMenu, nIndex, bSysMenu);
  int nCount = pPopupMenu->GetMenuItemCount();
  CCmdUI cmd;//创建自动更新类
  cmd.m_pMenu = pPopupMenu;
  cmd.m_nIndexMax = nCount;//MSDN上未介绍的成员变量
  for (int i = 0; i < nCount; i ++)
  {
    UINT nID = pPopupMenu->GetMenuItemID(i);
    if (nID != 0)//如果不是分隔符
    {
      cmd.m_nIndex = i;
      cmd.m_nID = nID;
      cmd.DoUpdate(this, TRUE);//MSDN上未介绍的成员函数,可以找到自动更新宏,传入CCmdUI指针,来执行自动更新
    }
  }
}