virtual bool AppendTextColumn( const wxString &label, size_t model_column );
virtual bool AppendToggleColumn( const wxString &label, size_t model_column );
virtual bool AppendProgressColumn( const wxString &label, size_t model_column );
+ virtual bool AppendDateColumn( const wxString &label, size_t model_column );
virtual bool AppendColumn( wxDataViewColumn *col );
virtual size_t GetNumberOfColumns();
virtual bool DeleteColumn( size_t pos );