在对话初始化函数里,注册事件反应器
    CInputPointMonitor::AddPointMonitor(MxDraw::GetDatabase(m_hDrawOcx)->GetDocument()->inputPointManager());
    //...

    // 在对话框销毁时，返注销事件反应器

    void CTestDlg::OnDestroy()
    {
        // 注消鼠标事件反应器

        CInputPointMonitor::RemovePointMonitor(MxDraw::GetDatabase(m_hDrawOcx)->GetDocument()->inputPointManager());
        // ...
    }

    // 在反应器里处理动态提示事件,显示实体信息
    Mcad::ErrorStatus CInputPointMonitor::MonitorInputPointToolTip(IN const McDbObjectIdArray& pickedEntities,
        IN const McGePoint3d& pickedPoint,
        IN CString& sNewToolTipString
        )
    {
        if(!pickedEntities.isEmpty())
        {
            AcDbObjectId entId = pickedEntities[0];
            AcDbObjectPointer<AcDbEntity> spEnt(entId,AcDb::kForRead);
            if(spEnt.openStatus() == Acad::eOk)
            {
                CString sClassName = spEnt->isA()->name();

                AcDbHandle handle;
                spEnt->getAcDbHandle(handle);
                TCHAR szHandle[256];
                handle.getIntoAsciiBuffer(szHandle);

                CString sLayerName;
                {
                    AcDbObjectPointer<AcDbLayerTableRecord> spLayerTableRec(spEnt->layerId(),AcDb::kForRead);
                    if(spLayerTableRec.openStatus() == Acad::eOk)
                    {
                        LPCTSTR pszLayerName = NULL;
                        spLayerTableRec->getName(pszLayerName);
                        sLayerName = pszLayerName;
                    }
                }

                sNewToolTipString.Format(_T("类名:%s,层名:%s,名柄:%s"),sClassName,sLayerName,szHandle);
            }
        }
        return Mcad::eOk;
    }