How does Message Mapping work?

After a "dummy" app. has been created(buttons menus, dialogs,etc...) how do I begin creating processes for these controls to actually do something?

Or when the user resizes the window, let's say I want the app to do several things following this event,etc...

And are "clean-up" procedures usually necassary for these operations?

Generalizations are O.K.

Your best step is to have a look at the following tutorial;
Sunlight's tutorials

Here's the generated message map (comments removed)-

Code:

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BEGIN_MESSAGE_MAP(CmfcApp, CWinApp)
        ON_COMMAND(ID_APP_ABOUT, OnAppAbout)
        ON_COMMAND(ID_FILE_NEW, CWinApp::OnFileNew)
        ON_COMMAND(ID_FILE_OPEN, CWinApp::OnFileOpen)
        ON_COMMAND(ID_FILE_PRINT_SETUP, CWinApp::OnFilePrintSetup)
END_MESSAGE_MAP()

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ON_COMMAND is the message. When your app gets this message it will check which of your buttons/menus(ID_APP_ABOUT, ID_FILE_NEW) etc have recieved it. It will then call the function that will respond to the message (OnAppAbout, OnFileNew).

But with MFC, you shouldn't have to code this yourself as the class wizard should take you through the steps where you assign messages to the Object ID's and then create the function for the handling of the message.

I think the sizing is handled by the code that MFC generates on start up, but you could check the function CWnd::OnSize which will provide info on resizing.

Disclaimer - I've hardly ever used MFC so some/all of this may be not exactly accurate.

Thank You!

And where exactly in the code should this be placed?

Re:MFC

I have no interest in MFC! I realize that it probably simplifies programming windows 100 fold, but I would rather just learn the standard API. No offense or anything!;)

This code is MFC.

if you are only interested in learning the api you use a switch statement in your window procedure to process the messages.

Get hold of petzold's programming windows.He explains this very well.

Quote:

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Originally posted by Sebastiani
I have no interest in MFC! I realize that it probably simplifies programming windows 100 fold, but I would rather just learn the standard API. No offense or anything!;)

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No, problem. I prefer the straight API. I assumed you got the title of your post from some MFC code, my fault.

It works on a similar principle using the API, as stoned coder has stated you need to write your message handling code in your window procedure. So that it will capture the WM_COMMAND messages.

here is some code from petzold to illustrate what you need to do.....

Code:

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#include <windows.h>
#include <math.h>

#define NUM 1000
#define TWOPI (2*3.14159)

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,PSTR szCmdLine,int iCmdShow)

{
        static TCHAR szAppName[]=TEXT("SineWave");
        HWND hwnd;
        MSG msg;
        WNDCLASS wndclass;

        wndclass.style=CS_HREDRAW | CS_VREDRAW;
        wndclass.lpfnWndProc=WndProc;
        wndclass.cbClsExtra=0;
        wndclass.cbWndExtra=0;
        wndclass.hInstance=hInstance;
        wndclass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
        wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);
        wndclass.hbrBackground=(HBRUSH) GetStockObject(WHITE_BRUSH);
        wndclass.lpszMenuName=NULL;
        wndclass.lpszClassName=szAppName;

        if (! RegisterClass(&wndclass))
        {
                MessageBox(NULL,TEXT("This program requires Windows NT!"),szAppName,MB_ICONERROR);
                return 0;
        }

        hwnd=CreateWindow(szAppName,TEXT("Sine wave using polyline function!"),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstance,NULL);

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

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

LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)
{
        static int cxClient,cyClient;
        HDC hdc;
        int i;
        PAINTSTRUCT ps;
        POINT apt[NUM];

        switch(message)
        {
        case WM_SIZE:
                cxClient=LOWORD(lParam);
                cyClient=HIWORD(lParam);
                return 0;
        case WM_DESTROY:
                PostQuitMessage(0);
                return 0;
        case WM_PAINT:
                hdc=BeginPaint(hwnd,&ps);
                MoveToEx(hdc,0,cyClient/2,NULL);
                LineTo(hdc,cxClient,cyClient/2);
                for (i=0;i<NUM;i++)
                {
                        apt[i].x=i*cxClient/NUM;
                        apt[i].y=(int) (cyClient/2*(1-sin(TWOPI*i/NUM)));
                }
                Polyline(hdc,apt,NUM);
                return 0;
        }
        return DefWindowProc(hwnd,message,wParam,lParam);
}

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Wow, thanks! I didn't realize that I was already "message-mapping", just got confused by the phrase!

And thanks for the code, it helped me see that...

And yes, I know, I know, get Petzold...but right now I am a poor old chap and so I am trying to jump-start with tutorials and the like till I recieve my check from those poor bastards I'm falsly suing for that little "slip and fall" incident at the Grocer's(See my tutorial "How to Fall Like a Pro...and Settle Fast" on my new website)...

ever heard of a library ?? :p

Hmm...thanks! Never thought of that. Probably nothing, but I'll try anyway...Good Suggestion, though.

That damn echo.........