/// <summary>
        /// Sets whether to show lines with totals.  setJWorksheet() must have been called
        /// with a non-null worksheet prior to this method.  The worksheet will be updated instantly. </summary>
        /// <param name="showTotals"> whether to show lines with totals in the worksheet. </param>
        public virtual void setShowTotals(bool showTotals)
        {
            __showTotals = showTotals;
            _sortOrder   = null;

            if (__showTotals)
            {
                _rows = __data[__COL_ID].Count;
            }
            else
            {
                _rows = __rowMap.Count;
            }
            __worksheet.refresh();
        }