🚀 go-pugleaf

"Sam" <skneife3@wanadoo.fr> wrote in message
news:40ee3b69@newsgroups.borland.com...

> The compiler refused. It seems that a class can't has
> a callback as method, that is right ?

Typically, to make a class method work as a callback, the method has to be
declared as 'static'.  However, in this particular case, you are using a
window procedure.  The VCL has a special function, MakeObjectInstance(),
that can convert a non-static class method into a window procedure callback.
For example:

    class TMyClass
    {
    private:
        void* Ptr;
    public:
        TMyClass();
        ~TMyClass();
    };

    TMyClass::TMyClass()
    {
        Ptr = MakeObjectInstance(NewWindowProc);
        // you can use Ptr anywhere you need to assign a callback window
procedure
    }

    TMyClass::~TMyClass()
    {
        FreeObjectInstance(Ptr);
    }

    void __fastcall TMyClass::NewWindowProc(TMessage &Message)
    {
        ...
        Message.Result = DefWindowProc(hSomeWnd, Message.Msg,
Message.WParam, Message.LParam);
    }


Gambit