Question

I’ve just made a simple C++ Window and added a menu, but when I click on the menu, specifally “About” i want to show a simply MessageBox but I can’t – because it doesn’t show.

LPCWSTR App_Name = TEXT("TestApp");
LPCWSTR App_Title = TEXT("TestTitle");

const int windowWidth = 480;
const int windowHeight = 480;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int iCmdShow)
{
    WNDCLASS wc;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    wc.hbrBackground = (HBRUSH)GetStockObject( WHITE_BRUSH );
    wc.hCursor = LoadCursor( NULL, IDC_ARROW );
    wc.hIcon = LoadIcon( NULL, IDI_APPLICATION );
    wc.hInstance = hInstance;
    wc.lpfnWndProc = WndProc;
    wc.lpszClassName = App_Name;
    wc.lpszMenuName = MAKEINTRESOURCE(MNU_MAINMENU);
    wc.style = CS_HREDRAW | CS_VREDRAW;

    RegisterClass(&wc); 

    RECT rc;
    GetWindowRect(GetDesktopWindow(), &rc);

    long screenWidth = rc.right;
    long screenHeight = rc.bottom;

    HWND hwnd = CreateWindow
    (
        App_Name,
        App_Title,
        WS_MINIMIZEBOX | WS_SYSMENU,
        (screenWidth / 2) - (windowWidth / 2), (screenHeight / 2)-(windowHeight/2),
        windowWidth, windowHeight,
        NULL, NULL,
        hInstance, NULL
    );


    ShowWindow(hwnd, iCmdShow );
    UpdateWindow(hwnd);

    MSG msg;

    while( GetMessage( &msg, NULL, 0, 0 ) )
    {
        TranslateMessage( &msg );
        DispatchMessage( &msg );
    }

    return msg.wParam;
}

and the MessageBox…:

LRESULT CALLBACK WndProc(HWND hwnd,UINT message, WPARAM wparam, LPARAM lparam)
{   
        switch( message )
        {

        case WM_COMMAND:
            id = LOWORD(wparam);
            event = LOWORD(wparam);
            switch(id)
            {
                case MNU_HELP_ABOUT:
                MessageBox(NULL, TEXT("TEXT"), TEXT("TITLE"), MB_OK | MB_ICONINFORMATION);
                break;
            }
        break;

        }
}

Menu works, cause I’ve added a Quit and such so I know it responds to the clicks on the menu but when I click the About button you hear the popup sound but there’s no MessageBox showing.

Any ideas?

Answer 1

I figured it out, somehow. Problem was because I haven’t done anything in WM_CREATE, or that that “nothing” was on the form – White background, or something. As soon as I started adding controls (buttons) to the Window it suddenly appeared where it didn’t before. Just weird…