C++ Classes

When creating a class in C++ that will hold data for an application

• Derive it from CObject
• Implement a Serialize method
• Implement the = operator
• Implement a copy constructor
• Include afxtempl.h in the stdafx.h file
• Define a type for a CArray of this class
• Include a global method for serializing elements in the CArray.
• Call the Serialize method of the class from the Serialize method of the Document.

In order to use the template classes like CArray, it is necessary to add the following line at the end of the stdafx.h file
#include <afxtempl.h>

Here is an example of a header file: data.h

class CData: public CObject {
  DECLARE_SERIAL(CData)
  public:
    CData();
    virtual ~CData();
    const CData& operator=(const CData& data);
    CData(const CData& data);
    void Serialize(CArchive &ar);

  public:
    int m_nAge;
    double m_dGPA;
};

template <> void AFXAPI SerializeElements <CData> ( CArchive& ar, 
    CData* pData, INT_PTR nCount );

typedef CArray<CData, CData&> CDataArray;

Here is the corresponding implementation: data.cpp

IMPLEMENT_SERIAL(CData, CObject, 0)

CData::CData() {
  m_nAge = 18;
  m_dGPA = 2.0;
}

CData::~CData() {
}

const CData& CData::operator=(const CData& data) {
  m_nAge = data.m_nAge;
  m_dGPA = data.m_dGPA;
  return *this;
}

CData::CData(const CData& data) {
  *this = data;
}

void CData::Serialize(CArchive &ar) {
  if (ar.IsStoring()) {
    ar << m_nAge << m_dGPA;
  } else {
    ar >> m_nAge >> m_dGPA;
  }
}

template <> void AFXAPI SerializeElements <CData> ( CArchive& ar, 
    CData* pData, INT_PTR nCount )
{
    for ( int i = 0; i < nCount; i++, pData++ )
    {
        // Serialize each CData object
        pData->Serialize( ar );
    }
}