Thread: 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?

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;
}