void CCommandManager::DViewTW45()
    {
        //
        if(!Mx::ActiveArxDoc()->IsModelSpace() )
        {
            acutPrintf(_T("n 视图的旋转命令只能在模形空间中使用"));
            return ;
        }

        McDbDatabase* pDatabase = Mx::mcdbHostApplicationServices()->workingDatabase();
        
        // 得到当前视口的id.
        McDbObjectPointer<McDbViewportTableRecord> spViewport(pDatabase->GetDocument()->getAcitveViewportId(),
            McDb::kForWrite);

        if(spViewport.openStatus() != Mcad::eOk)
        {
        
            return;
        }

        double dAng = spViewport->viewTwist();
        dAng = dAng + PI / 4.0; 

        if(dAng > 2PI)
        {
            dAng = fmod(dAng,2PI);
        }

        if(MxT::IsEqual(dAng,2PI,0.0001) )
        {
            dAng = 0.0;
        }
        spViewport->setViewTwist(dAng);
    }