virtual void DoSetItemClientData( int n, void* clientData );
virtual void* DoGetItemClientData( int n ) const;
virtual void DoSetItemClientObject( int n, wxClientData* clientData );
virtual void DoSetItemClientData( int n, void* clientData );
virtual void* DoGetItemClientData( int n ) const;
virtual void DoSetItemClientObject( int n, wxClientData* clientData );