ARX 实体的表达方式

ytcadtools

实体表达方式:handle, ObjectID,ads_name,指针point
- h8 Q9 a& g2 C; aObject Arx中,表达实体的方式主要有handle, ObjectID,ads_name,指针point;这些方式之间有什么区别呢?
, d" y1 N& ?) C  o. n, X2 qHandle:  永远不变,存在DWG文件中;
ObjectId:每次打开一个图,所有的对象都分得一个ObjectId,这个ObjectId维持不变,直到DWG被关闭
Point: 每次得到它,它总在变,就算它代表的实体是不变的.
5 o+ Q" B' z& n# \* `7 K% Iads_name 同 Point一样

5 ^- r4 t* y; J; V# K以下函数是常用的:
Acad::ErrorStatus
1 N: J) G2 T( q: H: t- NAcDbDatabase::acdbOpenObject(AcDbObject*& obj, AcDbObjectId id, AcDb::OpenMode mode,
                    Adesk::Boolean openErasedObject = Adesk::kFalse)
  z# ?5 ]( e) W& LAcad::ErrorStatus
getAcDbObjectId(AcDbObjectId& retId,Adesk::Boolean createIfNotFound,
" @4 y) a5 d" t3 L* s+ M3 C$ S           const AcDbHandle& objHandle,Adesk::UInt32 xRefId=0);
# Z; ~2 P) F7 t: N" j+ O" j; E
, u* m& F* n' @& L" L3 MAcDbObject* pObject;
' L' s! e- I) t1 J4 \. f4 o! V6 cAcDbHandle handle;
; ?: d) F% M* I  q7 B0 F
; {; ~. B  W( _2 e: RpObject->getAcDbHandle(handle);
acdbGetAdsName(ads_name& objName,AcDbObjectId objId);
acdbGetObjectId(AcDbObjectId& objId,ads_name objName);
acdbHandEnt(const char * handle,ads_name entres);