Serialization problem in VC++ 6.0

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I am having a project which is designed in VC++ 6.0 language. I got one class say CSplitDoc which is derived from CDocument class, this class having n numbers of other classes object.

I did apply serialization functionality for each class. Each class having some variables.. these variables values are store in a encrypted format in a text file... So whenever my application will start i can open saved condition file.

My problem is that whenever I add a new variable in any other class then VC++ serialization functionality is not working... So again I have to create encrypted format text file... which is very much time consuming.

So can someone pls suggest me some solution for such problem... asap...

Thank U in advance.

Posted 22-Aug-11 23:54pm

nhasmita

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Eugen Podsypalnikov · Answer 1 · 2011-08-23T01:00:00

Please observe also the following technique :) :

C++

// class CYourDocument : public CDocument

/*virtual*/ void CYourDocument::Serialize(CArchive& ar)
{
  static DWORD sdwVersion(2); // 2 = new member(s) = new version

  CDocument::Serialize(ar);

  if (ar.IsStoring()) {
    ar << sdwVersion;

    ar << m_ver1_member;
    ar << m_ver2_member;
  } else {
    ar >> sdwVersion;

    ar >> m_ver1_member;
    if (2 <= sdwVersion) {
      ar >> m_ver2_member;
    }
  }
}

P.S. Please remember also
to initialize your new member(s) in the default constructor.

CPallini · Answer 2 · 2011-08-23T00:06:00

Solution 1

Unfortunately the MFC serialization mechanism is fragile (at least from 'versioning' standpoint). You may use this trick:

Change only the store methods.
Import the 'old' archive.
Update, if needed, the old objects with the new features, serialize them.
Now change the load methods too.

I know, is frustrating.

Posted 23-Aug-11 0:06am

CPallini

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nhasmita 23-Aug-11 23:59pm

Thank U for the solution..
Can u pls elaborate ur solution with example.