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Creating modeless dialog box (VC++)

Posted on 2004-10-14
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Last Modified: 2011-04-14
Hi,
I intend to create a simple dialog box using VC++. The code snippet is given below. The call of CreateDialog always returns a NULL handle. Why is it so?

--Sachin


// dialog.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "resource.h"

BOOL
InitMainDialog ( HINSTANCE hInstance,
                         int nCmdShow);

BOOL CALLBACK
MainDlgProc ( HWND hwDlg,
                    UINT uiMsg,
                    WPARAM wParam,
                    LPARAM lParam );

HINSTANCE      ghInstance;
HWND            ghWnd;

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
      MSG msg;
      if (!hPrevInstance ) {
             if (!InitMainDialog ( hInstance, nCmdShow ) ) {
                  return FALSE;
            }
      }
      while (GetMessage (&msg, NULL, 0, 0)) {
            TranslateMessage ( &msg );
            DispatchMessage ( &msg );
      }
      return 0;
}

BOOL
InitMainDialog (HINSTANCE hInstance,
                        int nCmdShow)
{
      // Save instance handle in a global variable
      ghInstance      = hInstance;
      
      char *strInResource      = MAKEINTRESOURCE ( IDD_MAIN_DLG );
      // Try to create a dialog box
      ghWnd            = CreateDialog ( hInstance,
                                                 MAKEINTRESOURCE (IDD_MAIN_DLG),
                                                 NULL,
                                                 (DLGPROC) MainDlgProc );
      if ( ghWnd == NULL ) {
            return FALSE;
      }

      ShowWindow ( ghWnd, SW_SHOW );
      return TRUE;
}


BOOL CALLBACK
MainDlgProc ( HWND hwDlg,
                    UINT uiMsg,
                    WPARAM wParam,
                    LPARAM lParam )
{
      switch ( uiMsg ) {
      
      }
      return TRUE;
}




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Question by:m_sachin
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5 Comments
 
LVL 13

Expert Comment

by:SteH
ID: 12306224
You should call GetLastError in the case that the call to CreateDialog fails. The reason for failing is stored in a "global" error value.

Can you post that value.
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LVL 39

Expert Comment

by:itsmeandnobodyelse
ID: 12306568
The CreateDialog returned not NULL after i added resource file to the project.

However, as there was no WM_PAINT handler there was no output ;-)

Regards, Alex
0
 

Author Comment

by:m_sachin
ID: 12306694
Error value returned is 1406
--Sachin
0
 
LVL 13

Accepted Solution

by:
SteH earned 125 total points
ID: 12306788
error code help:
1406 Cannot create a top-level child window.

Your dialog seems to have child flag and the window will be top level. You need to make remove child flag and add toplevel instead.
0
 
LVL 39

Expert Comment

by:itsmeandnobodyelse
ID: 12306802
1406 == //  Cannot create a top-level child window

Your dialog resource has Child Window property. You have to switch to Popup or Overlapped Style.

Regards, Alex

P. S. You'll find all errors in "winerror.h"
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