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Can't Access Application Class data members.

Posted on 1998-11-25
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Last Modified: 2013-11-20
Hi,
I have and SDI application. I have declared few public
variables to the Application Class as well as MainFrame class.

How do I access these variables from a new class created
by me? When I used AfxMainWnd()-> or AfxGetApp()->
it gave the following errors respectively.
error C2039: 'EntityFileName' : is not a member of 'CWnd'
error C2039: 'EntityFileName' : is not a member of 'CWinApp'

I had declared 'EntityFileName' as a Cstring in the respective classes. Is it that only base class members are
accessed using those functions?

What is the solution???
Thanks.
 
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Question by:leena_mary
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4 Comments
 
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Accepted Solution

by:
pagladasu earned 200 total points
ID: 1325270
You see, ::AfxGetApp() returns a pointer to CWinApp class and not your own application class, which, let us say is called CMyApp
To get over this problem, you do the following:

CMyApp *m_pApp;
m_pApp=(CMyApp *)::AfxGetApp();
// access your variable now like m_pApp->EntityFileName
For the variable in the MainFrame class you could do something like this:
CMainFrame *m_pFrWnd=::AfxGetApp()->m_pMainWnd;
//and then m_pFrWnd->EntityFileName

Hope this will sort your problem.
Thanks and best of luck.
pagladasu


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LVL 4

Expert Comment

by:pagladasu
ID: 1325271
Hi,
Just an afterthought. You can interact with all the classes in a Document-View application architecture.
The important thing is that most funtions will return a pointer to the base class. Since with a pointer to the base class, you can only access the base class members even if you make it point to a derived class object. The only way it helps is in implementing run time polymorphism. If you want this pointer to access derived class members also, you must do an exclusive type-casting.
Hope this will clear up your doubts. Any other queries, feel free to clarify them. My email address is:
espical@hotmail.com
Thanks.
pagladasu.
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Author Comment

by:leena_mary
ID: 1325272
Thanks, pagladasu.

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Author Comment

by:leena_mary
ID: 1325273
Thanks, pagladasu.

0

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