Why are my WINAPI messages not reaching my window procedure?

Question

I am using a winapi dialog as my root HWND for a window class. The program compiles and displays perfectly, but when I click on the buttons, nothing is responsive, almost like the messages aren't reaching my window procedure, or said procedure is never being called. How can I ensure that the messages are working correctly and I'm handling them properly for what I'm trying to do?

Simplified WinMain in main.c:

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    LPSTR lpCmdLine, int nCmdShow)
{
    static char szAppName[] = TEXT ("AppName"); // Does not display, remove later
    HWND hwnd;
    MSG msg;

    WNDCLASS wndclass;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = DlgProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = DLGWINDOWEXTRA;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_MAIN));
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH) (COLOR_BTNFACE + 1);
    wndclass.lpszMenuName  = MAKEINTRESOURCE(IDC_MAINMENU);
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL,
                   TEXT("This program requires Windows NT!"),
                   szAppName,
                   MB_ICONERROR);
        return 0;
    }

    hwnd = CreateDialog(hInstance, MAKEINTRESOURCE(IDD_MAIN), 0, NULL);
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

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

Simplified DlgProc (written in C++ and registered for use in C):

LRESULT CALLBACK DlgProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
    switch(Message)
    {
        case WM_INITDIALOG:
            MessageBeep(0); // Does not sound, even if I change the case to WM_CREATE
        break;
        case WM_COMMAND:
            switch(LOWORD(wParam))
            {
                // Handle buttons/statics inside the dialog, they do nothing
            }
        case WM_CLOSE:
            EndDialog(hwnd, 0);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
        default:
            return FALSE;
    }
    return TRUE;
}

dialog in resource file:

IDD_MAIN DIALOG DISCARDABLE  0, 0, 207, 156
STYLE WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX
CAPTION "AppTitle"
FONT 8, "MS Sans Serif"
BEGIN
    // Internal statics and buttons
END

Answer 1

Follow the Using the code which is in Microsoft GitHub repository steps to complete your program. You should set your dialog Class Name = AppName in resource file and Change WM_INITDIALOG back to WM_CREATE in WndProc that you call DlgProc.