Incorrect values in member functions

[Derek Baker]

I am trying to develop a wrapper class for a Windows MDI application.

This is the class declaration for the application:

#ifndef INCLUDEGUARD_MDIAPP_H
#define INCLUDEGUARD_MDIAPP_H

#include <windows.h>

void ShowError();

class MDIApp
{
    private:
            HINSTANCE    hInst;
               HMENU        hMenu;
            HWND        hwndClient;
             
    public:
            MDIApp(HINSTANCE hInstance, int iCmdShow);
           
    private:
            int OnCommand(HWND hwnd, UINT Message, WPARAM wParam,
                   LPARAM lParam);
               
            int OnCreate(HWND hwnd, UINT Message, WPARAM wParam,
                 LPARAM lParam);
  
            static LRESULT CALLBACK MainWndProc(HWND hwnd, UINT Message,
                WPARAM wParam, LPARAM lParam);
};

#endif

The problem is in the On.... member functions, the values of the members are seemingly incorrect.

For example, debugging code:

TCHAR szBug[100];
            wsprintf(szBug, "hInstance  %Ix", hInstance);
            MessageBox (NULL, szBug,
                   TEXT("Main"), 0);

in main and the constructor, reports hInstance and hInst as 0x400000. However identical code in OnCreate reports various incorrect figures for hInst:

int MDIApp::OnCreate(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
    TCHAR szBug[100];
            wsprintf(szBug, "hInst  %Ix", hInst);
            MessageBox (NULL, szBug,
                   TEXT("MDIApp::OnCreate"), 0);   
   
    static TCHAR szClientName [] = TEXT("Text Client");
       
    CLIENTCREATESTRUCT ccs;
    
     ccs.hWindowMenu     = hMenu;
     ccs.idFirstChild     = IDM_FIRSTCHILD;
    
      hwndClient = CreateWindow("MDICLIENT",
                               szClientName,
                               WS_CHILD | WS_CLIPCHILDREN | WS_VISIBLE,
                               0,
                               0,
                               0,
                               0,
                               hwnd,
                               (HMENU) 1,
                               hInst,
                               (PSTR) &ccs);
    
   
    if(!hwndClient)
    {
        MessageBox (NULL, TEXT("Could not create client window"),
                   TEXT("MDIApp::OnCreate"), 0);
    }
   
   
    ShowWindow(hwndClient, SW_SHOW);                               
    
     return 0;
}

What is going on?

Apologies for the length of the post, but I wanted to include all the information I thought relevant.

Thanks in advance

Derek

[Derek Baker]

In case anyone is interested, I got the answer.

See here:

http://arstechnica.infopop.net/OpenTopic/page?a=tpc&s=50009562&f=6330927813&m=3880982845

Derek

[Yiannis Mandravellos]

I had posted the answer to you problem in another thread, but as it seems you never bothered to look at it...

http://sourceforge.net/forum/message.php?msg_id=1846407

Yiannis.

[Derek Baker]

My apologies Yiannis,

I did look at your post. But at that time I was looking at a slightly different problem: as you helpfully pointed out my failure to initialise mythis during WM_CREATE.

I completely missed the fact I was getting the pointer out of  lParam instead of (LPCREATESTRUCT)lParam)->lpCreateParams. As this thread shows:

http://www.experts-exchange.com/Programming/Programming_Platforms/Win_Prog/Q_20482207.html

I'd totally got the idea there was nothing wrong there, and it took tiny on the thread I posted earlier to set me straight.

I do appreciate the help you gave, and it was useful.

You may be pleased to know the class is now working - of course you may not be pleased, if you now don't like me!

Thanks

Derek

[Yiannis Mandravellos]

> You may be pleased to know the class is now working - of course you may not be pleased, if you now don't like me!

Why not like you? You are where I was 6 months ago, when I was starting my C++ wrapper classes for WinAPI...

The fact that you didn't notice my answer, cost you three more days on your problem (judging by the messages timestamps). That's fine with me ;))

Cheers,
Yiannis.

[Derek Baker]

Cool of you.

You might like to know, it took me some five days to get the class working at the most basic level - only five times what I originally estimated!

Derek