关于模态/非模态对话框不响应菜单的UPDATE_COMMAND_UI消息（对对WM_INITMENUPOPUP消息的处理）

对于模态非模态对话框默认是不响应菜单的UPDATE_COMMAND_UI消息的，需要增加对WM_INITMENUPOPUP消息的处理以后，才可以响应UPDATE_COMMAND_UI。

void CXXXDlg::OnInitMenuPopup(CMenu* pPopupMenu, UINT nIndex, BOOL bSysMenu)
{
 CDialog::OnInitMenuPopup(pPopupMenu, nIndex, bSysMenu);

// TODO: Add your message handler code here

 if(!bSysMenu && pPopupMenu)
 {
  CCmdUI cmdUI;
  cmdUI.m_pOther = NULL;
  cmdUI.m_pMenu = pPopupMenu;
  cmdUI.m_pSubMenu = NULL;

  UINT count = pPopupMenu->GetMenuItemCount();
  cmdUI.m_nIndexMax = count;
  for(UINT i=0; i<count; i++)
  {
   UINT nID = pPopupMenu->GetMenuItemID(i);
   if(-1 == nID || 0 == nID)
   {
    continue;
   }
   cmdUI.m_nID = nID;
   cmdUI.m_nIndex = i;
   cmdUI.DoUpdate(this, FALSE);
  }
 }
}