使用智能指针 获得当前所有图层的ID

以下是二段代码：功能是获得当前所有图层的ID

int CLayerOperate::GetAllLayerIds()
{
    LayerIds.removeAll();
    AcDbLayerTable *pLT;
    acdbHostApplicationServices()->workingDatabase()->getLayerTable(pLT,AcDb::kForRead);

    AcDbLayerTableIterator *pLTI;

    AcDbObjectId idTemp;
    pLT->newIterator(pLTI);

    for (pLTI->start(); !pLTI->done(); pLTI->step())
    {
        pLTI->getRecordId(idTemp);
        LayerIds.append(idTemp);
    }
    delete pLTI;
    pLT->close();

    return LayerIds.length();

以下是使用智能指针，好处就是不用删指针，安全。

int LayerCommon::GetAllLayerIds(AcDbObjectIdArray& idLayerArr)
{
    // 得到当前图形的层块 游天居士到此一游 
    AcDbLayerTablePointer pLayerTbl(acdbCurDwg(),AcDb::kForRead);
    if (pLayerTbl.openStatus() != eOk)
    {
        return NULL;
    }

    AcDbLayerTableIterator* pLTI = NULL; 
   　 pLayerTbl->newIterator(pLTI);

    AcDbObjectId idTemp;
    for (pLTI->start(); !pLTI->done(); pLTI->step())
    {
        if (Acad::eOk == pLTI->getRecordId(idTemp))
        {
            idLayerArr.append(idTemp);
        }
    }
    delete pLTI;

    return idLayerArr.length();
}

//  DESCRIPTION
//
//  The template classes defined in this header file provide
//  simplified "management" (i.e., opening, closing, creating,
//  deleting) of AcDbObject's upon construction and destruction.
//  The constructor provides the necessary arguments to open the
//  object and the destructor closes the object.  During the
//  lifetime of the object, clients use operator->() to
//  manipulate the opened object.  These classes also simplify
//  creating and deletion of objects.
// 
//  One base class, AcDbObjectPointerBase provides the basic
//  services of opening and closing objects.  Derived classes
//  provide the real interface to open objects of various types
//  derived from AcDbObject.  They usually provide additional
//  constructors that know about the particular ways of opening
//  an object.  The following template classes are defined in
//  this header file.
//
//  AcDbObjectPointerBase<T_OBJECT>
//
//       This class provides the basic services and defines the
//       basic contracts for using the smart pointers derived
//       from it.  You normally don't use this class directly,
//       but may use it to define a derived class to add
//       constructors that know how to open an object derived
//       from AcDbObject in alternate forms.
//
//  AcDbObjectPointer<T_OBJECT>
//
//       This class allows you to access any AcDbObject-based
//       object given its object ID.  The following pre-defined
//       typedefs are available.
//
//       AcDbDictionaryPointer
//       AcDbEntityPointer
//
//  AcDbSymbolTablePointer<T_OBJECT>
//
//       This class allows you to access the symbol tables
//       associated with every AcDbDatabase.  You can specify
//       an object ID or a particular database.  The following
//       pre-defined typedefs are available for individual
//       symbol-table types.
//
//       AcDbBlockTablePointer
//       AcDbDimStyleTablePointer
//       AcDbLayerTablePointer
//       AcDbLinetypeTablePointer
//       AcDbRegAppTablePointer
//       AcDbTextStyleTablePointer
//       AcDbUCSTablePointer
//       AcDbViewTablePointer
//       AcDbViewportTablePointer
//
//       Note that to open a "plain" symbol table, you may use
//       AcDbObjectPointer<AcDbSymbolTable>.
//
//  AcDbSymbolTableRecordPointer<T_OBJECT>
//
//       This class allow you to access symbol-table records by
//       object ID or by name.  The following pre-defined
//       typedefs are available for individual symbol-table
//       record types.
//
//       AcDbBlockTableRecordPointer
//       AcDbDimStyleTableRecordPointer
//       AcDbLayerTableRecordPointer
//       AcDbLinetypeTableRecordPointer
//       AcDbRegAppTableRecordPointer
//       AcDbTextStyleTableRecordPointer
//       AcDbUCSTableRecordPointer
//       AcDbViewTableRecordPointer
//       AcDbViewportTableRecordPointer
//
//       Note that to open a "plain" symbol record, you may use
//       AcDbObjectPointer<AcDbSymbolTableRecord>.
//
// These classes are designed to be type-safe replacements for
// explicitly using acdbOpenObject(), acdbOpenAcDbObject(), and
// acdbOpenAcDbEntity().  Using these classes incur opening and
// close objects, which, under certain circumstances, may be
// better managed using transactions. 

 

 

typedef AcDbSymbolTablePointer<AcDbBlockTable>     AcDbBlockTablePointer;
typedef AcDbSymbolTablePointer<AcDbDimStyleTable>  AcDbDimStyleTablePointer;
typedef AcDbSymbolTablePointer<AcDbLayerTable>     AcDbLayerTablePointer;
typedef AcDbSymbolTablePointer<AcDbLinetypeTable>  AcDbLinetypeTablePointer;
typedef AcDbSymbolTablePointer<AcDbRegAppTable>    AcDbRegAppTablePointer;
typedef AcDbSymbolTablePointer<AcDbTextStyleTable> AcDbTextStyleTablePointer;
typedef AcDbSymbolTablePointer<AcDbUCSTable>       AcDbUCSTablePointer;
typedef AcDbSymbolTablePointer<AcDbViewTable>      AcDbViewTablePointer;
typedef AcDbSymbolTablePointer<AcDbViewportTable>  AcDbViewportTablePointer;