Problem creating a Dialog Box

This is a discussion on Problem creating a Dialog Box within the Windows Programming forums, part of the Platform Specific Boards category; This is giving me an error 'Invalid Window Handle' but I can't figure out why. Code: LRESULT CALLBACK MainWinProc(HWND hWnd, ...

  1. #1
    Darkness Prevails Dark_Phoenix's Avatar
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    Houston, Texas
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    Problem creating a Dialog Box

    This is giving me an error 'Invalid Window Handle' but I can't figure out why.

    Code:
    LRESULT CALLBACK MainWinProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
    {
        switch (Msg)
        {
            case WM_CREATE:
            {
                char str[80];
                if (DialogBoxParam(GetModuleHandle(NULL),
                                   MAKEINTRESOURCE(IDD_NEWUSER),
                                   hWnd,
                                   NewUserDlgProc,
                                   (LPARAM)str) <= 0)
                {
                    ShowWinError();
                }
            }
            break;
     
            case WM_CLOSE:
            DestroyWindow(hWnd);
            break;
     
            case WM_DESTROY:
            PostQuitMessage(0);
            break;
     
            default:
            return DefWindowProc (hWnd, Msg, wParam, lParam);
        }
        return 0;
    }
    I am tring to opn a dialog for the user to enter a user name and have the dialog pass that back to the main window

    The call to DialogBoxParam is throwing the invalid handle error. Any ideas?
    Last edited by Dark_Phoenix; 05-30-2009 at 08:20 AM.
    Using Code::Blocks and Windows XP

    In every hero, there COULD be a villain!

  2. #2
    Darkness Prevails Dark_Phoenix's Avatar
    Join Date
    Oct 2006
    Location
    Houston, Texas
    Posts
    174
    OK, I figured it out... forgot to put a break in my DialogProc. Anyway, here is what I have... It works but I want to know if it is right?

    Code:
    LRESULT CALLBACK MainWinProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
    {
        switch (Msg)
        {
            case WM_CREATE:
            {
                std::string str;
                DialogBoxParam(GetModuleHandle(NULL),
                               MAKEINTRESOURCE(IDD_NEWUSER),
                               hWnd,
                               NewUserDlgProc,
                               (LPARAM)&str);
            }
            BringWindowToTop(hWnd);
            break;
    
            case WM_CLOSE:
            DestroyWindow(hWnd);
            break;
    
            case WM_DESTROY:
            PostQuitMessage(0);
            break;
    
            default:
            return DefWindowProc (hWnd, Msg, wParam, lParam);
        }
    
        return 0;
    }
    
    
    BOOL CALLBACK NewUserDlgProc(HWND hDialog, UINT Msg, WPARAM wParam, LPARAM lParam)
    {
        static std::string *str;
        switch (Msg)
        {
            case WM_INITDIALOG:
            str = (std::string*)lParam;
            break;
    
            case WM_COMMAND:
            switch (LOWORD(wParam) )
            {
                case IDB_OK:
                {
                    char chStr[80];
                    GetDlgItemText(hDialog, IDE_EDIT, chStr, 80);
                    *str = chStr;
                    SendMessage(hDialog, WM_CLOSE, NULL, NULL);
                }
                break;
            }
            break;
    
            case WM_CLOSE:
            EndDialog(hDialog, (LPARAM)str);
            break;
    
            default:
            return FALSE;
        }
        return TRUE;
    }
    Using Code::Blocks and Windows XP

    In every hero, there COULD be a villain!

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