ARX 实体的表达方式

ytcadtools

实体表达方式:handle, ObjectID,ads_name,指针point
Object 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?
0 E5 i! r( |8 l9 LHandle:  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.
( V8 h' e( \4 j1 @# nads_name 同 Point一样
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! ~1 f8 Z8 U( k' Q以下函数是常用的:
Acad::ErrorStatus
AcDbDatabase::acdbOpenObject(AcDbObject*& obj, AcDbObjectId id, AcDb::OpenMode mode,
                    Adesk::Boolean openErasedObject = Adesk::kFalse)
Acad::ErrorStatus
& n$ a# Z/ l; ~3 LgetAcDbObjectId(AcDbObjectId& retId,Adesk::Boolean createIfNotFound,
: S' v! n+ q* ~8 Q6 C2 e* t2 v           const AcDbHandle& objHandle,Adesk::UInt32 xRefId=0);
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( }; ]/ j& U6 B! o3 ?3 ZAcDbObject* pObject;
6 Q% c6 C7 ~1 |) g/ L0 V1 C+ l1 C  |AcDbHandle handle;
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+ I/ y; A% X3 g2 g, w* fpObject->getAcDbHandle(handle);
8 `/ L5 R/ v/ N/ Z# W& l# S7 ~acdbGetAdsName(ads_name& objName,AcDbObjectId objId);
+ h. |7 m# x; A2 s4 A, b3 h" FacdbGetObjectId(AcDbObjectId& objId,ads_name objName);
- ~% E1 ~+ _$ W- f. f- aacdbHandEnt(const char * handle,ads_name entres);