透過封存儲存和載入 CObjects

透過存檔儲存和載入 CObject 需要額外考量。 在某些情況下，您應該呼叫物件的 Serialize 函式，其中 CArchive 物件作為 Serialize 呼叫的參數，而不是使用 << 的 >> 或 CArchive 運算符。 請記住的重要事實是，CArchive>>運算子會根據儲存檔案封存先前寫入的CObject資訊，在記憶體中構建CRuntimeClass。

因此，不論CArchive您使用 <<>> 和 Serialize 運算符，還是呼叫 ，取決於您是否需要載入封存以根據先前儲存CRuntimeClass的資訊動態重建物件。 在下列情況下使用 函 Serialize 式：

• 當反序列化物件時，您事先知道物件的確切類別。

• 還原序列化的物件時，您已經為物件配置好記憶體。

下列範例說明案例：

class CMyObject : public CObject
{
   // ...Member functions
public:
   CMyObject() {}
   virtual void Serialize(CArchive &ar);

   // Implementation
protected:
   DECLARE_SERIAL(CMyObject)
};

class COtherObject : public CObject
{
   // ...Member functions
public:
   COtherObject() {}
   virtual void Serialize(CArchive &ar);

   // Implementation
protected:
   DECLARE_SERIAL(COtherObject)
};

class CCompoundObject : public CObject
{
   // ...Member functions
public:
   CCompoundObject();
   ~CCompoundObject();
   virtual void Serialize(CArchive &ar);

   // Implementation
protected:
   CMyObject m_myob;       // Embedded object
   COtherObject *m_pOther; // Object allocated in constructor
   CObject *m_pObDyn;      // Dynamically allocated object
   //..Other member data and implementation

   DECLARE_SERIAL(CCompoundObject)
};

IMPLEMENT_SERIAL(CMyObject, CObject, 1)
IMPLEMENT_SERIAL(COtherObject, CObject, 1)
IMPLEMENT_SERIAL(CCompoundObject, CObject, 1)

CCompoundObject::CCompoundObject()
{
   m_pOther = new COtherObject; // Exact type known and object already
                                //allocated.
   m_pObDyn = NULL;             // Will be allocated in another member function
                                // if needed, could be a derived class object.
}

CCompoundObject::~CCompoundObject()
{
   delete m_pOther;
}

void CCompoundObject::Serialize(CArchive &ar)
{
   CObject::Serialize(ar);  // Always call base class Serialize.
   m_myob.Serialize(ar);    // Call Serialize on embedded member.
   m_pOther->Serialize(ar); // Call Serialize on objects of known exact type.

   // Serialize dynamic members and other raw data
   if (ar.IsStoring())
   {
      ar << m_pObDyn;
      // Store other members
   }
   else
   {
      ar >> m_pObDyn; // Polymorphic reconstruction of persistent object
      //load other members
   }
}

總而言之，如果您的可串行化類別定義內嵌CObject為成員，則不應該使用該物件的CArchive<<和>>運算符，而應改為呼叫Serialize函式。 此外，如果您的可序列化類別將指標CObject（或衍生自CObject的物件）定義為成員，但在自己的建構函式中建構這個其他物件，您也應該呼叫Serialize。

另請參閱

串行化：串行化物件