void CTestCommands::ReadExData()
    {
        ads_name entName;
        ads_point pt;
        if(acedEntSel(_T("选择读取的扩展数据的实体:"),entName,pt) != RTNORM)
        {
            return;
        }
        AcDbObjectId objId;
        if(acdbGetObjectId(objId,entName) != Acad::eOk)
            return;

        AcDbObjectPointer<AcDbEntity> spEnt(objId,AcDb::kForRead);
        if(spEnt.openStatus() != Acad::eOk)
            return;

        struct resbuf* pExDataRb  = spEnt->xData(_T(""));

        if(pExDataRb == NULL)
        {
            acutPrintf(_T("n 没有扩展数据"));
        }
        else
        {
            CTestCommands::printResbufChain(pExDataRb);
        }
        acutRelRb(pExDataRb);
    }