How to access wm_command from outside the window function

Question

I'm building my first c++ project using classes (trying to get more experience) and now I'm stuck. I need to determine which button was pressed from my calculator application. The way I have my project set up is:

Windows.cpp

// Windows.cpp
#include <Windows.h>
#include <wchar.h>
#include "Resource.h"
#include "Application.h"

int WINAPI wWinMain(...)
{
    // after register class and create/show/update window ( winMain() )
    Application App(hwnd);
    App.Go();

    // Main message loop, etc.
    MSG msg;
    ZeroMemory(&msg,sizeof(msg));
    while(msg.message != WM_QUIT)
    {
      if(PeekMessage(&msg,NULL,0,0,PM_REMOVE))
      {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
      }
    }
    return 0;
}

Application.h

 #pragma once
 #include "Calculator.h"

class Application
{
public:
    Application(HWND hwnd);
    ~Application();
    void Go();

private:
    void Run();

private:
    Calculator calc;
};

Application.cpp:

// Application.cpp

#include "Application.h"

Application::Application(HWND hwnd)
: calc(hwnd)
{}
Application::~Application()
{}
void Application::Go()
{
    calc.Initiate(); // This function shows all my button controls for my calculator
    Run();
}

void Application::Run()
{
    // This is where i want to determine which button was pressed(if any)
    if(buttonONEwasPRESSED) { /* do stuff */ } // etc
}

I thought about adding a function to Calculator class to determine if a button was pressed, but I'm not sure how to access wm_command, or if theres another way. Then I could just call calc.IsButtonPressed().

Answer 1

You are stuck because you want to know which button was pressed. That reminds me some console programs dealing with user input.

That's not how to go with GUI. What you should do is code what to do when a button is pressed. That's event drived programming.

With standard Win32 application, the "event" for pushbutton press is WM_COMMAND.

For mapping a HWND to a C++ class with easy mapping between a WM_MESSAGE_X and an OnMessageX member function, see for example https://stackoverflow.com/a/20356046/1374704