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Designing Menus: Problem assigning events to menu item clicks

KaidzAccount (25)
First, here my code: (Compiled as C)
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#include <windows.h>

#define ID_FILE_EXIT 4001
#define ID_STUFF_GO  4002
#define ID_HELP_WTF  4003

#define WM_MYMESSAGE 4004

const char g_szClassName[] = "myWindowClass";

// Step 4: the Window Procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
		case WM_MYMESSAGE:
			MessageBox(hwnd, "", "", MB_OK);
		break;
		case WM_CREATE:
			{
			HMENU hMenu, hSubMenu;
			HICON hIcon, hIconSm;

			hMenu = CreateMenu();

			hSubMenu = CreatePopupMenu();
			AppendMenu(hSubMenu, MF_STRING, ID_FILE_EXIT, "&Exit");
			AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&File");

			hSubMenu = CreatePopupMenu();
			AppendMenu(hSubMenu, MF_STRING, ID_STUFF_GO, "&Go");
			AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&Stuff");

			hMyMenu = CreatePopupMenu();
			AppendMenu(hSubMenu, MF_STRING, ID_HELP_WTF, "&Wtf is this program for?");
			AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&Help");

			SetMenu(hwnd, hMenu);

			hIcon = LoadImage(NULL, "my_icon.ico", IMAGE_ICON, 32, 32, LR_LOADFROMFILE);
			if (hIcon)
				SendMessage(hwnd, WM_SETICON, ICON_BIG, (LPARAM)hIcon);
			else
				MessageBox(hwnd, "File not found: my_icon.ico", "ERROR", MB_OK | MB_ICONERROR);

			hIconSm = LoadImage(NULL, "my_icon.ico", IMAGE_ICON, 16, 16, LR_LOADFROMFILE);
			if (hIconSm)
				SendMessage(hwnd, WM_SETICON, ICON_SMALL, (LPARAM)hIconSm);
			else
				MessageBox(hwnd, "Failed to load small icon", "ERROR", MB_OK | MB_ICONERROR);
			}
		break;
		case WM_COMMAND:
			{
			switch (LOWORD(wParam))
				case ID_FILE_EXIT:
					{
						MessageBox(hwnd, "Bye!", "", MB_OK);
						PostMessage(hwnd, WM_CLOSE, 0, 0);
					}
				break;
				case ID_STUFF_GO:
					{
						PostMessage(hwnd, WM_MYMESSAGE, 0, 0);
					}
				break;
				case ID_HELP_WTF:
					{
						MessageBox(hwnd, "Your guess is as good as mine :)", "", MB_OK);
					}
				break;
			}
			break;
		case WM_LBUTTONDOWN:
			{
			char szFileName[MAX_PATH];
			HINSTANCE hInstance = GetModuleHandle(NULL);
			
			GetModuleFileName(hInstance, szFileName, MAX_PATH);
			MessageBox(hwnd, szFileName, "Executable Name:", MB_OK);
			}
		break;
		case WM_CLOSE:
            DestroyWindow(hwnd);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
        default:
            return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASSEX wc;
    HWND hwnd;
    MSG Msg;

    //Step 1: Registering the Window Class
    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.style         = 0;
    wc.lpfnWndProc   = WndProc;
    wc.cbClsExtra    = 0;
    wc.cbWndExtra    = 0;
    wc.hInstance     = hInstance;
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    wc.lpszMenuName  = NULL;
    wc.lpszClassName = g_szClassName;
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);

    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    // Step 2: Creating the Window
    hwnd = CreateWindowEx(
        WS_EX_CLIENTEDGE,
        g_szClassName,
        "The title of my window",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
        NULL, NULL, hInstance, NULL);

    if(hwnd == NULL)
    {
        MessageBox(NULL, "Window Creation Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

    // Step 3: The Message Loop
    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return Msg.wParam;
}


I'm following the Forger's WinAPI tutorial. The exact problem is that although clicking the menu File > Exit sends a message WM_CLOSE and closes the window as expected (following the message box), the 2 events I added for Stuff > Go and Help > Wtf is this program for don't work at all. And I can't understand why.

Last edited on
jrohde (107)
You didn't enclose your 'switch' statement in a block - so it only will execute the first statement afterward. Therefore you are able to get the first case to work, but the code after it is completely ignored. (Also there's a variable 'hMyMenu' where it should be 'hSubMenu', or this won't even compile).

I would encourage you also to get into the habit of enclosing any logic statement in a block, even if it's just a one-line statement, like this:

if (something) {
DoSomething();
}

It's easier to read and more concise, and if you want to quickly add a second statement later, the brackets are already there anyway. Not to mention FAR easier when looking for errors/debugging in a large program.


Last edited on
Lamblion (642)
What he's saying is that after your "case WM_COMMAND" statement, you have to have a switch statment, so it would look like this...

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case WM_COMMAND:
switch( LOWORD(wParam) )
{
     other stuff
}


The brackets you have after the WM_COMMAND are superflous.
Last edited on
KaidzAccount (25)
Thanks, solved.
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