objectARX 获取指定图层上所有实体ID

//获取指定图层上所有实体ID
AcDbObjectIdArray GetAllEntityId(const TCHAR* layername)
{
AcDbObjectIdArray entIds;
bool bFilterlayer = false;
AcDbObjectId layerId;
//获取指定图层对象ID
if (layername != NULL)
{
AcDbLayerTable *pLayerTbl = NULL;
acdbHostApplicationServices()->workingDatabase()->getSymbolTable(pLayerTbl, AcDb::kForRead);
if (!pLayerTbl->has(layername))
{
pLayerTbl->close();
return entIds;
}
pLayerTbl->getAt(layername, layerId);
pLayerTbl->close();
bFilterlayer = true;
}
//获得块表
AcDbBlockTable *pBlkTbl = NULL;
acdbHostApplicationServices()->workingDatabase()->getSymbolTable(pBlkTbl, AcDb::kForRead);
//块表记录
AcDbBlockTableRecord *pBlkTblRcd = NULL;
pBlkTbl->getAt(ACDB_MODEL_SPACE, pBlkTblRcd, AcDb::kForRead);
pBlkTbl->close();
//创建遍历器，依次访问模型空间中的每一个实体
AcDbBlockTableRecordIterator *it = NULL;
pBlkTblRcd->newIterator(it);
for (it->start(); !it->done(); it->step())
{
AcDbEntity *pEnt = NULL;
Acad::ErrorStatus es = it->getEntity(pEnt, AcDb::kForRead);
if (es == Acad::eOk)
{
if (bFilterlayer)//过滤图层
{
if (pEnt->layerId() == layerId)
{
entIds.append(pEnt->objectId());
}
}
else
{
//    entIds.append(pEnt->objectId());
pEnt->close();
}
}
}
delete it;
pBlkTblRcd->close();
return entIds;
}