Non-Virtual Interface (NVI)

class IuGUI : public IuUnknown
{

public:
    void OnDraw(HDC hDC)
    {
        this->OnOwnerDraw(hDC);
    }

private:
    virtual void OnOwnerDraw(HDC hDC) = 0;

};

class CuGUI :
    public IuGUI
{
public:
    CuGUI(void);
    ~CuGUI(void);

    virtual ULONG Release() 
    { 
        delete this;
        return 0;
    }

private:
    virtual void OnOwnerDraw(HDC hDC);
};