Serialization in non - Document/View arch. projects .

Introduction

This article will show you how you can serialize data to disk and retrieve it again in non doc/view architecture projects. Just follow the steps outlined.

Steps to follow

• Create a normal project as you usually do.
• Add the class which you would use to serialize the data. It might contain just normal variables or collection classes or any kind of data that you want to store.
  • Be sure to derive that class from CObject. Only then you can serialize the data.
  • Be sure to use the DECLARE_SERIAL macro inside.

//CInfo.h

class CInfo : public CObject
{
DECLARE_SERIAL(CInfo)

public:

    virtual void Serialize(CArchive& ar);
    int m_nIndex;
    CString m_strName;
};

• Add the serialization function in this class's .cpp file. Be sure to use the IMPLEMENT_SERIAL macro as shown.

//CInfo.cpp

#include "stdafx.h"
#include "CInfo.h"

IMPLEMENT_SERIAL(CInfo,CObject,1)

void CInfo::Serialize(CArchive& ar)
{
    if (ar.IsLoading()) // If you are loading data from the disk
    {
        ar >> m_strName;
        ar >> m_nIndex;
    }
    else // If you are storing data to the disk
    {
        ar << m_strName;
        ar << m_nIndex;
    }
}

• As this example is concerned with just 2 variables, assume that 2 edit controls have been created to accommodate the Index and the Name. Add 2 variables to those edit controls using the Class Wizard. Now the File to which the data has to be written or read from has to be defined. I do that simply by :-

// The Accounts.dat file is the 
// file that we are going to use 
// to save and read data

#define DATA_FILE _T("Accounts.dat") 

• Now, we write the code for storing the data to the disk. Here, m_bCanSave is declared in the header file as BOOL m_bCanSave; and in the constructor it has been initialized as m_bCanSave = FALSE;

void SaveRecords()                  
//  Code to serialize and save the data
{
    UINT nFlags = CFile::typeBinary | CFile::modeWrite;

    if (_access(DATA_FILE, 0))
    {
        nFlags |= CFile::modeCreate;            
        // The file doesn't exist, so create it
        
        m_bCanSave = TRUE;
    }
    else
    {
        int nTemp = _access(DATA_FILE, 6);  
        // Check Read Write Permissions

        if(nTemp==0)
            m_bCanSave = TRUE;
    }

    if (m_bCanSave)
    {
        CFile file;
        CFileException fe;

        // The file exists with read & write permissions
        if (file.Open(DATA_FILE, nFlags, &fe))
        {
            CArchive ar(&file, CArchive::store);
            UpdateData(TRUE);
            Info.m_nIndex = m_nIndex;
            Info.m_strName = m_strName;
            Info.Serialize(ar); // Serialize the data
        }
    }   
}

• Now , we write the code for reading the data from the disk.

void LoadRecords()
{
    if (_access(DATA_FILE, 6)==0) // If File Exists
    {
        CFile file;
        CFileException fe;

        if (file.Open(DATA_FILE,CFile::typeBinary | 
            CFile::modeRead, &fe))
        {
            CArchive ar(&file, CArchive::load);
            Info.Serialize(ar);
        }

    }

    m_nIndex = Info.m_nIndex;
    m_strName = Info.m_strName;
    UpdateData(FALSE);
}

Conclusion

That's it. A Simple tutorial for serialization is complete. You have a program that can serialize data to the disk and retrieve it later. You didn't know that serialization was so easy. Did you? All Luck and have a nice time.