创建AcDb2dPolyline实体

遍历AcDb2dPolyline实体的顶点坐标

    static void iterate(AcDbObjectId pLineId)
    {
        //打开AcDb2dPolyline对象
        AcDb2dPolyline *pPline;
        acdbOpenObject(pPline, pLineId, AcDb::kForRead);

        //获得多段线的矢量遍历器
        AcDbObjectIterator *pVertIter = pPline->vertexIterator();
        pPline->close();

        //对顶点进行遍历
        AcDb2dVertex *pVertex;
        AcGePoint3d location;
        AcDbObjectId vertexobjectId;
        for (int vertexNumber = 0; !pVertIter->done(); vertexNumber++, pVertIter->step())
        {
            //打开矢量对象
            vertexobjectId = pVertIter->objectId();
            acdbOpenObject(pVertex, vertexobjectId,AcDb::kForRead);

            //获得矢量对象的坐标
            location = pVertex->position();
            pVertex->close();

            //输出坐标
            acutPrintf(L"\nVertox %d location is : %0.3f, %0.3f, %0.3f", vertexNumber, location[X], location[Y], location[Z]);
        }
        delete pVertIter;
    }

创建AcDb2dPolyline实体

static void lzxARX_AcDbDatabaseCreatePolyline(void)
    {
        //设置多段线的四个矢量
        AcGePoint3dArray ptArr;
        ptArr.setLogicalLength(4);
        for (int i = 0; i < 4; i++) 
        {
            ptArr[i].set((double)(i/2), (double)(i%2), 0.0);
        }

        //动态创建一个AcDb2dPolyline对象，在ptArr中给出四个顶点位置
        //缺省的线宽为0
        AcDb2dPolyline *pNewPline = new AcDb2dPolyline(AcDb::k2dSimplePoly, ptArr, 0.0, Adesk::kTrue);

        //设置实体颜色
        pNewPline->setColorIndex(3);

        //获得块表对象指针
        AcDbBlockTable *pBlockTable;
        acdbHostApplicationServices()->workingDatabase()->getSymbolTable(pBlockTable, AcDb::kForRead);

        //获得模型空间块表记录指针
        AcDbBlockTableRecord *pBlockTableRecord;
        pBlockTable->getAt(ACDB_MODEL_SPACE, pBlockTableRecord, AcDb::kForWrite);

        pBlockTable->close();

        //将多段线对象添加数据库中并获得其对象ID
        AcDbObjectId plineObjId;
        pBlockTableRecord->appendAcDbEntity(plineObjId, pNewPline);

        pBlockTableRecord->close();

        //设置多段线对象所在的层为0层
        pNewPline->setLayer(L"0");

        pNewPline->close();

        iterate(plineObjId);
    }

程序执行结果：

在图上画了一条多段线，并在命令行中输出每个顶点坐标，如下：

Vertox 0 location is : 0.000, 0.000, 0.000
Vertox 1 location is : 0.000, 1.000, 0.000
Vertox 2 location is : 1.000, 0.000, 0.000
Vertox 3 location is : 1.000, 1.000, 0.000