internal void FromSortState(SortState ss)
        {
            this.SetAllNull();

            if (ss.ColumnSort != null && ss.ColumnSort.Value)
            {
                this.ColumnSort = ss.ColumnSort.Value;
            }
            if (ss.CaseSensitive != null && ss.CaseSensitive.Value)
            {
                this.CaseSensitive = ss.CaseSensitive.Value;
            }
            if (ss.SortMethod != null)
            {
                this.SortMethod = ss.SortMethod.Value;
            }

            int    iStartRowIndex    = 1;
            int    iStartColumnIndex = 1;
            int    iEndRowIndex      = 1;
            int    iEndColumnIndex   = 1;
            string sRef = ss.Reference.Value;

            if (sRef.IndexOf(":") > 0)
            {
                if (SLTool.FormatCellReferenceRangeToRowColumnIndex(sRef, out iStartRowIndex, out iStartColumnIndex, out iEndRowIndex, out iEndColumnIndex))
                {
                    this.StartRowIndex    = iStartRowIndex;
                    this.StartColumnIndex = iStartColumnIndex;
                    this.EndRowIndex      = iEndRowIndex;
                    this.EndColumnIndex   = iEndColumnIndex;
                }
            }
            else
            {
                if (SLTool.FormatCellReferenceToRowColumnIndex(sRef, out iStartRowIndex, out iStartColumnIndex))
                {
                    this.StartRowIndex    = iStartRowIndex;
                    this.StartColumnIndex = iStartColumnIndex;
                    this.EndRowIndex      = iStartRowIndex;
                    this.EndColumnIndex   = iStartColumnIndex;
                }
            }

            if (ss.HasChildren)
            {
                SLSortCondition sc;
                using (OpenXmlReader oxr = OpenXmlReader.Create(ss))
                {
                    while (oxr.Read())
                    {
                        if (oxr.ElementType == typeof(SortCondition))
                        {
                            sc = new SLSortCondition();
                            sc.FromSortCondition((SortCondition)oxr.LoadCurrentElement());
                            // limit of 64 from Open XML specs
                            if (this.SortConditions.Count < 64)
                            {
                                this.SortConditions.Add(sc);
                            }
                        }
                    }
                }
            }
        }