subclass.h

在编写图形程序

////////////////////////////////////////////////////////////////
//
#ifndef _SUBCLASSW_H
#define _SUBCLASSW_H

class /*AFX_EXT_CLASS*/ CSubclassWnd : public CObject {
public:
	DECLARE_DYNAMIC(CSubclassWnd);
	CSubclassWnd();
	~CSubclassWnd();

	// Subclass a window. Hook(NULL) to unhook (automatic on WM_NCDESTROY)
	BOOL	HookWindow(HWND  hwnd);
	BOOL	HookWindow(CWnd* pWnd)	{ return HookWindow(pWnd->GetSafeHwnd()); }
	BOOL	IsHooked()					{ return m_hWnd!=NULL; }

	friend LRESULT CALLBACK HookWndProc(HWND, UINT, WPARAM, LPARAM);
	friend class CSubclassWndMap;

#ifdef _DEBUG
	virtual void AssertValid() const;
	virtual void Dump(CDumpContext& dc) const;
#endif

protected:
	HWND				m_hWnd;				// the window hooked
	WNDPROC			m_pOldWndProc;		// ..and original window proc
	CSubclassWnd*	m_pNext;				// next in chain of hooks for this window

	// Override this to handle messages in specific handlers
	virtual LRESULT WindowProc(UINT msg, WPARAM wp, LPARAM lp);
	LRESULT Default();				// call this at the end of handler fns
};

#endif // _SUBCLASSW_H