c++ objectarx二次开发删除指定图层下所有实体

您可以使用以下代码在 AutoCAD 中删除指定图层下的所有实体：

AcDbLayerTable *pLayerTbl;
acdbHostApplicationServices()->workingDatabase()->getSymbolTable(pLayerTbl, AcDb::kForRead);

AcDbLayerTableRecord *pLayerTblRcd;
AcDbObjectId layerId = AcDbObjectId::kNull;
if (pLayerTbl->getAt("LayerName", pLayerTblRcd, AcDb::kForWrite) == Acad::eOk)
{
    layerId = pLayerTblRcd->objectId();
    pLayerTblRcd->close();
}

pLayerTbl->close();

if (!layerId.isNull())
{
    AcDbBlockTable *pBlockTbl;
    acdbHostApplicationServices()->workingDatabase()->getSymbolTable(pBlockTbl, AcDb::kForRead);

    AcDbBlockTableRecord *pBlockTblRcd;
    if (pBlockTbl->getAt(ACDB_MODEL_SPACE, pBlockTblRcd, AcDb::kForWrite) == Acad::eOk)
    {
        AcDbBlockTableRecordIterator *pBlkTblRcdIter;
        pBlockTblRcd->newIterator(pBlkTblRcdIter);

        for (; !pBlkTblRcdIter->done(); pBlkTblRcdIter->step())
        {
            AcDbEntity *pEnt;
            if (pBlkTblRcdIter->getEntity(pEnt, AcDb::kForWrite) == Acad::eOk)
            {
                if (pEnt->layerId() == layerId)
                {
                    pEnt->erase();
                }
                pEnt->close();
            }
        }

        delete pBlkTblRcdIter;
        pBlockTblRcd->close();
    }
    pBlockTbl->close();
}

其中，"LayerName" 部分需要替换为您要删除的图层的名称。请注意，此代码仅适用于 AutoCAD 和 ObjectARX 开发环境，不适用于其他 CAD 软件。