// - ArxProject2.partLine command (do not rename)
    static void ArxProject2partLine(void)
    {
        // Add your code for command ArxProject2.partLine here
        ads_name entName;
        ads_point pt;
        acedEntSel( _T("\n选择："),entName,pt);//得到选中的实体

AcDbObjectId ObjId;//得到实体ID
        
        if( acdbGetObjectId(ObjId,entName) != Acad::eOk )//如果没有选中的实体则返回
        {
            acutPrintf( _T("\nno"));
            return;
        }

AcDbEntity* pEnt;//得到实体
        if( acdbOpenObject(pEnt,ObjId,AcDb::kForRead) == Acad::eOk)
        {
            acutPrintf( _T("\nok"));
            AcDbLine* pLine = (AcDbLine* )pEnt;//强制转换
            AcGePoint3d ptStart = pLine->startPoint();//得到起点
            AcGePoint3d ptEnd = pLine->endPoint();
            pEnt->close();

//根据点和线的方向生成点组，绘制线段
            int nPart = 5;//五等分
            AcGeVector3d Vect = (ptEnd - ptStart)/nPart;//矩阵，点与点的差集平分可得到
            for (int n=0; n<nPart; n++)
            {
                AcDbObjectId ObjIdNew;
                MakeLine(ptStart+n*Vect,ptStart+(n+1)*Vect,ObjIdNew);//等分线段的方法
            }

//将选中的线段删除，
            if( acdbOpenObject(pEnt,ObjId,AcDb::kForWrite) == Acad::eOk )
            {
                pEnt->erase();
                pEnt->close();
            }
        }
    }

//将实体添加到数据库
    //cad中的实体最终都要添加到数据库中才能被显示(图纸其实是一个数据库格式的)，所以它的作用就是添加实体到数据库中
    static Acad::ErrorStatus AddToDb(AcDbEntity* ent, AcDbObjectId& objId)
    {    
        Acad::ErrorStatus      es;
        AcDbBlockTable*        pBlockTable;
        AcDbBlockTableRecord*  pSpaceRecord;

if ((es = acdbHostApplicationServices()->workingDatabase()->getBlockTable(pBlockTable, AcDb::kForRead))
            != Acad::eOk) {
                return es;
        }

if ((es = pBlockTable->getAt(ACDB_MODEL_SPACE, 
            pSpaceRecord,
            AcDb::kForWrite)) != Acad::eOk) {
                return es;
        }

if ((es = pBlockTable->close()) != Acad::eOk) {
            return es;
        }
        if ((es = pSpaceRecord->appendAcDbEntity(objId, ent)) != Acad::eOk) {
            return es;
        }

return pSpaceRecord->close();

}
    private://画线函数
        static void MakeLine(AcGePoint3d ptStart,AcGePoint3d ptEnd,AcDbObjectId lineId)
        {
            AcDbLine *pLine = new AcDbLine(ptStart,ptEnd);
            if(AddToDb(pLine,lineId)!=Acad::eOk)//传入指针，传出id
                AfxMessageBox( _T("加入实体到数据库失败！"));
            pLine->close();
        }