Encapsulation of the Window

Here's my window creation code.

Code:

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#include <windows.h>

// Declare WndProcedure




LRESULT CALLBACK WndProcedure(HWND hWnd, UINT uMsg,
                          WPARAM wParam, LPARAM lParam);

INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
              LPSTR lpCmdLine, int nCmdShow)
{
        MSG        Msg;
        HWND      hWnd;
        HRESULT          hRet;
        WNDCLASSEX WndClsEx;

        // Populate the WNDCLASSEX structure
        WndClsEx.cbSize        = sizeof(WNDCLASSEX);
        WndClsEx.style        = CS_HREDRAW | CS_VREDRAW;
        WndClsEx.lpfnWndProc  = WndProcedure;
        WndClsEx.cbClsExtra    = 0;
        WndClsEx.cbWndExtra    = 0;
        WndClsEx.hIcon        = LoadIcon(NULL, IDI_APPLICATION);
        WndClsEx.hCursor      = LoadCursor(NULL, IDC_ARROW);
        WndClsEx.hbrBackground = (HBRUSH)(COLOR_HIGHLIGHT+1);//(HBRUSH)GetStockObject(WHITE_BRUSH);
        WndClsEx.lpszMenuName  = NULL;
        WndClsEx.lpszClassName = "MyWindow";
        WndClsEx.hInstance    = hInstance;
        WndClsEx.hIconSm      = LoadIcon(NULL, IDI_APPLICATION);

       
 /* COLOURS :)
COLOR_ACTIVEBORDER
COLOR_ACTIVECAPTION
COLOR_APPWORKSPACE
COLOR_BACKGROUND
COLOR_BTNFACE
COLOR_BTNSHADOW
COLOR_BTNTEXT
COLOR_CAPTIONTEXT
COLOR_GRAYTEXT
COLOR_HIGHLIGHT
COLOR_HIGHLIGHTTEXT
COLOR_INACTIVEBORDER
COLOR_INACTIVECAPTION
COLOR_MENU
COLOR_MENUTEXT
COLOR_SCROLLBAR
COLOR_WINDOW
COLOR_WINDOWFRAME
COLOR_WINDOWTEXT
*/
 
 
 
 // Register the class
        RegisterClassEx(&WndClsEx);





        // Create the window object
        hWnd = CreateWindow("MyWindow",
                          "Rich's Window",
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          NULL,
                          NULL,
                          hInstance,
                          NULL);
                         




                         
                         
       
        // Verify window creation
        if( !hWnd ) // If the window was not created,
                return 0; // stop the application

        // Show the window
        ShowWindow(hWnd, SW_SHOWNORMAL);
        UpdateWindow(hWnd);

        //  message pump
        while( (hRet = GetMessage( &Msg, NULL, 0, 0 )) != 0)
        {
                if (hRet == -1)
                {
        // handle the error and possibly exit
                }
                else
                {
                        TranslateMessage(&Msg);
                        DispatchMessage(&Msg);
                }
        }

return 0;

}



LRESULT CALLBACK WndProcedure(HWND hWnd, UINT Msg,
                          WPARAM wParam, LPARAM lParam)
{
    switch(Msg)
    {
    case WM_DESTROY:
        // user wants to exit
        PostQuitMessage(WM_QUIT);
        break;
    default:
        // Hand off unprocessed messages to DefWindowProc
        return DefWindowProc(hWnd, Msg, wParam, lParam);
    }
   
    return 0;
}

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I am unsure of how to put it in a class so I can create as many windows as i want in an application.

-What do i do with the message handler? Do i declare it static
-Once classed to i added member functions like set window caption, using sendmessage.

A description of how to do it would be fantastic :), i want to try and do as much myself, its the only way i learn.

If you add a class , then the minimum data you keep there would be the HWND. Now, once you have that and have a static wndproc, you have to find a way to get to the C++ object for a particular window and there are many ways to do it.

One way is to make a framework where the framework maintains a mapping of HWNDs to the C++ objects. ( MFC style )
Another way could be to , in case they are your own registered classes, to store the C++ object pointer as data for the window using SetWindowLong ( beware that if you overwrite this area ), it will be messy.

You can come up with any other way..

Below is a simple implementation of a C++ encapsulation of the window process.

It uses a window property (SetPropA, GetPropA) to store the window objects pointer. (Create all windows on the heap to be sure it's valid. Also, in WM_NCDESTROY, you can 'delete this' so when a window is destroyed the destructor gets called.

Code:

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class Window
{
public:
    // Normal
protected:
    HWND Handle;
    virtual INT_PTR WindowProcess(UINT message,WPARAM wParam,LPARAM lParam) throw();
private:
    static INT_PTR __stdcall HandleWindowProcess(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam) throw();
};

/////////////////////////////////////////////////////////////
//// HandleWindowProcess

INT_PTR __stdcall Window::HandleWindowProcess(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam) throw()
{
    // pass your this pointer as the last parameter to CreateWindowEx
    if (message == WM_NCCREATE)
    {
        LPCREATESTRUCT lpCreate = reinterpret_cast<LPCREATESTRUCT>(lParam);

        Window * pWindow = reinterpret_cast<Window *>(lpCreate->lpCreateParams);
        /* Comment out above line and uncomment the below for an MDI Child Window

        LPMDICREATESTRUCT lpMdiCreate = reinterpret_cast<LPMDICREATESTRUCT>(lpCreate->lpCreateParams);
        Window * pWindow = reinterpret_cast<Window *>(lpMdiCreate->lParam);

        */

        pWindow->Handle = hWnd;

        // Set a window property to store the window object pointer
        ::SetPropA(hWnd,"WindowObject",reinterpret_cast<HANDLE>(pWindow));

        return pWindow->WindowProcess(message,wParam,lParam);
    }
    else
    {
        // try to obtain a pointer to the window object
        Window * pWindow = reinterpret_cast<Window *>(::GetPropA(hWnd,"WindowObject"));
        if (pWindow != NULL)
        {
            return pWindow->WindowProcess(message,wParam,lParam);
        }
        else
        {
            // not a window object
            return ::DefWindowProc(hWnd,message,wParam,lParam);
        }
    }
}

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Thanks, I'll book mark this thread and give it a shot sometime soon.

Hmm looking at james example maybe I should finish learning OPP for C++ first, I see type casting and throws, haven't looked at them yet.