Thread: Creating a Window Class

So I just about have my basic window class finished. I have it down to 1 unresolved external error. I cannot for the life of me trace it down. Here is what I have so far.
MyWindowClass.h

Code:

#ifndef MYWINDOWCLASS_H_INCLUDED
#define MYWINDOWCLASS_H_INCLUDED
 
class CBaseWindow;
typedef std::map<HWND, CBaseWindow*> hWndMap;
 
class CBaseWindow
{
public:
CBaseWindow() { }
virtual ~CBaseWindow() { }
static LRESULT CALLBACK GlobalWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
virtual LRESULT CALLBACK InstanceWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
void Attach(HWND h, CBaseWindow *pClass) { m_ThisMap[h] = pClass; }
static hWndMap m_ThisMap;
};
 
class CWindow : public CBaseWindow
{
public:
CWindow();
~CWindow() { }
bool Create(HINSTANCE hInstance, int nCmdShow, LPCSTR szClassName, LPCSTR szWindowName);
int Run();
LRESULT CALLBACK InstanceWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
BOOL NavPaneDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
BOOL ViewPaneDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
 
private:
WNDCLASSEX m_wc;
HWND m_hwnd;
MSG m_Msg;
HINSTANCE m_hInstance;
LPCSTR m_ClassName;
LPCSTR m_WindowName;
HWND m_hNavPane;
HWND m_hViewPane;
};
 
#endif // MYWINDOWCLASS_H_INCLUDED

MyWindowClass.cpp

Code:

#include "stdafx.h"
 
hWndMap CBaseWindow::m_ThisMap;
 
LRESULT CBaseWindow::GlobalWndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    hWndMap::iterator it = m_ThisMap.find(hWnd);
    if (it != m_ThisMap.end() )
    {
        CWindow *pClass = (CWindow*)it->second;
        return pClass->InstanceWndProc(hWnd, msg, wParam, lParam);
    }
    return DefWindowProc(hWnd, msg, wParam, lParam);
}
 
LRESULT CWindow::InstanceWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
         // Menu Bar Commands
        case WM_COMMAND:
        {
            switch(LOWORD(wParam) )
            {
                // Select Menubar-File-Exit
                case ID_FILE_EXIT:
                {
                    PostMessage(hwnd, WM_CLOSE, 0, 0);
                }
                break;
            }
        }
        case WM_CLOSE:
        {
            DestroyWindow(hwnd);
        }
        break;
        case WM_DESTROY:
        {
            PostQuitMessage(0);
        }
        break;
        default:
        {
            return DefWindowProc(hwnd, msg, wParam, lParam);
        }
    }
    return 0;
}
 
CWindow::CWindow()
{
    m_hwnd = NULL;
    m_hNavPane = NULL;
    m_hViewPane = NULL;
}
 
bool CWindow::Create(HINSTANCE hInstance, int nCmdShow, LPCSTR szClassName, LPCSTR szWindowName)
{
    m_hInstance  = hInstance;
    m_ClassName  = (LPCSTR)szClassName;
    m_WindowName = (LPCSTR)szWindowName;
 
    //  Register the Window Class
    m_wc.cbSize        = sizeof(WNDCLASSEX);
    m_wc.style         = 0;
    m_wc.lpfnWndProc   = GlobalWndProc;
    m_wc.cbClsExtra    = 0;
    m_wc.cbWndExtra    = 0;
    m_wc.hInstance     = hInstance;
    m_wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    m_wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    m_wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    m_wc.lpszMenuName  = MAKEINTRESOURCE(IDR_MYMENU);
    m_wc.lpszClassName = m_ClassName;
    m_wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);
 
    if(!RegisterClassEx(&m_wc))
    {
        SHOWERROR("Window Registration Failed!");
        return false;
    }
 
    // Create the window
    m_hwnd = CreateWindowEx(WS_EX_CLIENTEDGE,
                            m_ClassName,
                            m_WindowName,
                            WS_MAXIMIZE | WS_OVERLAPPEDWINDOW | WS_VSCROLL | WS_HSCROLL,
                            0,0,1280,1020,
                            NULL,
                            NULL,
                            m_hInstance,
                            NULL);
    if(m_hwnd == NULL)
    {
        SHOWERROR("Window Creation Failed!");
        return false;
    }
    Attach(m_hwnd, this);
    ShowWindow(m_hwnd, nCmdShow);
    UpdateWindow(m_hwnd);
    return true;
}
 
int CWindow::Run()
{
    while(GetMessage(&m_Msg, NULL, 0, 0) > 0)
    {
       TranslateMessage(&m_Msg);
       DispatchMessage(&m_Msg);
    }
    return m_Msg.wParam;
}

main.cpp

Code:

#include "stdafx.h"
 
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine, int nCmdShow)
{
    CWindow *pWindow = new CWindow();
    // Create the Window
    int msg;
    if (pWindow->Create(hInstance, nCmdShow, "MainWindowClass", "My Window") )
    {
        // Run the application (start the message loop)
        msg = pWindow->Run();
    }
    // Clean up resources
    if(pWindow)
    {
        delete pWindow;
        pWindow = NULL;
    }
    return msg;
}

and the error I'm getting is

Code:

unresolved external symbol "public: virtual long __stdcall CBaseWindow::InstanceWndProc(struct HWND__ *,unsigned int,unsigned int,long)" (?InstanceWndProc@CBaseWindow@@UAGJPAUHWND__@@IIJ@Z)

OK, so what am I missing?

I don't see CBaseWindow::InstanceWndProc implemented anywhere...

You should delete the

virtual LRESULT CALLBACK InstanceWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);

from your CBaseWindow because you didn't implement it.

You implemented it in CWindow instead.

If you need more help, try the C++ Win32 API Wrapper