Re: CMap in CMap

Fred <>
Mon, 09 Nov 2009 13:12:07 +0100
Giovanni Dicanio a ?crit :

I think the problem is that CMap derives from CObject, and CObject
declares *private* copy constructor and operator=.
In fact, if you go to the CObject definition in <afx.h> MFC header file
(at least in VS2008) you can read:

   CObject(const CObject& objectSrc); // no implementation
   void operator=(const CObject& objectSrc); // no implementation

So, CMap doesn't offer a copy semantic "out of the box".

I would suggest you to use STL std::map container, which is designed in
a way to implement copy semantic out-of-the-box.

In particular, your CMap's:

 CMap <int, int, CIAMMetaDataAttribute,
 CMap <int, int, int, int> alternateValue;

could be substitued by the following std::map's:

 std::map< int, CIAMMetaDataAttribute > EvtAttributes;
 std::map< int, int, > alternateValue;

Note that std::map does not have the (IMHO) confusing ARG_KEY and
ARG_VALUE templates.
std::map just has the Key and Type template arguments (in its basic form):

map Class (Standard C++ Library)


Hi Giovanni,
thanks for the tip.
In the meantime, I managed to solve my problem by declaring a pointer to
the second CMap instead of the CMap itself.
******* IAMMetaDataAttribute.h **********
#pragma once

class CIAMMetaDataAttribute

     CString m_name;
     bool m_multiValued;
     CString m_transform;
     CString resourceId;

     CMap <int, int, int, int> *alternateValue;

So I guessed I could get out with it this way... but your post about the
std::map object puzzled me ;)
Could you tell me more about this std::map thing? Is it more efficient
than CMap? It seems to be less convenient to manipulate, isn't it?

Thanks again for your help.


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