basewindow.h

#include <windows.h>

template <class DERIVED_TYPE>
class BaseWindow
{
public:
	static LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
	{
		DERIVED_TYPE *pThis = NULL;

		if(uMsg == WM_NCCREATE)
		{
			CREATESTRUCT* pCreate = (CREATESTRUCT*)lParam;
			pThis = (DERIVED_TYPE*) pCreate->lpCreateParams;
			SetWindowLongPtr(hwnd, GWLP_USERDATA, (LONG_PTR)pThis);

			pThis->m_hwnd = hwnd;
		}
		else
		{
			pThis = (DERIVED_TYPE*)GetWindowLongPtr(hwnd, GWLP_USERDATA);
		}
		if(pThis)
		{
			return pThis->HandleMessage(uMsg, wParam, lParam);
		}
		else
		{
			return DefWindowProc(hwnd, uMsg, wParam, lParam);
		}
	}

	BaseWindow() : m_hwnd(NULL) {}

	BOOL Create(
		PCWSTR lpWindowName,
		DWORD dwStyle,
		DWORD dwExStyle = 0,
		int x = CW_USEDEFAULT,
		int y = CW_USEDEFAULT,
		int nWidth = 800, //CW_USEDEFAULT,
		int nHeight = 600, //CW_USEDEFAULT,
		HWND hWndParent = 0,
		HMENU hMenu = 0)
	{
		WNDCLASS wc = {0};

		wc.lpfnWndProc = DERIVED_TYPE::WindowProc;
		wc.hInstance = GetModuleHandle(NULL);
		wc.lpszClassName = ClassName();

		wc.hbrBackground = (HBRUSH)(COLOR_BACKGROUND+1);
		wc.hCursor = (HCURSOR)LoadCursor(NULL,IDC_ARROW);

		RegisterClass(&wc);

		m_hwnd = CreateWindowEx(
			dwExStyle, ClassName(), lpWindowName, dwStyle, x, y,
			nWidth, nHeight, hWndParent, hMenu, GetModuleHandle(NULL), this);

		return (m_hwnd ? TRUE : FALSE);
	}

	HWND Window() const {return m_hwnd;}

protected:
	virtual PCWSTR ClassName() const = 0;
	virtual LRESULT HandleMessage(UINT uMsg, WPARAM wParam, LPARAM lParam) = 0;

	HWND m_hwnd;
};