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Newbie problem with SerializeElements

Posted on 2002-05-20
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Last Modified: 2013-11-20
Hi

I'm getting the following error while implementing SerializeElements:

"'CArchive::CArchive': cannot access protected member declared in class 'CArchive'"

This is the code I am using:

template <> 
void AFXAPI SerializeElements <CStockData>
( CArchive& ar, CStockData* pNewSD, int nCount )
{    
     for ( int i = 0; i < nCount; i++, pNewSD++ )
          pNewSD->Serialize( ar );
}

and it is defined in the header as:

template <> 
void AFXAPI SerializeElements <CStockData>
( CArchive& ar, CStockData* pNewSD, int nCount );

outside of the class declarations.

The SerializeElements code is sitting in a class (CStockDataList: public CList< CStockData, CStockData & > ) that adds CStockData objects (derived from CObject) to a list.  The StockData.h has been included in StockDataList.h as well as afxtempl.h for CList.


CStockData has been serialised by using
IMPLEMENT_SERIAL(CStockData, CObject, 1) in the .cpp and
DECLARE_SERIAL(CStockData) in the .h

I use the following code for CStockData Serialize  (All data members are protected):

void CStockData::Serialize(CArchive ar)
{
     if (ar.IsStoring ())
          ar << m_date << m_dblPrice << m_strFund;
     else
          ar >> m_date >> m_dblPrice >> m_strFund;
}



I'm still pretty new to MFC so I'm not really sure what the error message is trying to tell me, or if I'm even looking in the right place for the solution.  I've looked in the MSDN and the code I'm using for SerializeElements seems to be correct, so I'm stumped as to what I'm missing.

Any help would be greatly appreciated.

Thanks in advance.
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Question by:boomshanker
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3 Comments
 
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Accepted Solution

by:
kender_a earned 400 total points
ID: 7156510
Hi!

It looks like your function is geared for MFC CObjects & CArchives.

You don't need to write a template function for that (unless you have some special non-MFC reasons for making a template functions). Since method Serialize(...) is defined as virtual in the CObject, it's more conventional to declare your function like this:

 void AFXAPI SerializeElements
 ( CArchive& ar, CObject* pNewSD, int nCount );

Implementation remains the same as yours.

You are getting the error regarding protected CArchive::CArchive because somewhere in your code you have constructed a CArchive without constructor arguments i.e.:

 CArchive ar;

The problem is caused by CStockData::Serialize(CArchive ar)
- it receives CArchive by value, but it shoud receive it by reference.
Should be CStockData::Serialize(CArchive& ar).

Sincerely,
Kender

 
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LVL 1

Author Comment

by:boomshanker
ID: 7160490
Thanks!!!

I had actually given up on this project (and almost on MFC!!!).

You were right on the money.  I was using CArchive ar instead of &ar.  As soon as I changed that, it worked.

Thanks again.
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LVL 1

Expert Comment

by:kender_a
ID: 7161479
You're wellcome at any time!

Kender
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