// TODO: Hyperlink cell range

        /// <summary>
        /// Insert a hyperlink.
        /// </summary>
        /// <param name="RowIndex">The row index.</param>
        /// <param name="ColumnIndex">The column index.</param>
        /// <param name="HyperlinkType">The type of hyperlink.</param>
        /// <param name="Address">The URL for web pages, the file path for existing files, a cell reference (such as Sheet1!A1 or Sheet1!A1:B5), a defined name or an email address. NOTE: Do NOT include the "mailto:" portion for email addresses.</param>
        /// <param name="Display">The display text. Set null or an empty string to use the default.</param>
        /// <param name="ToolTip">The tooltip (or screentip) text. Set null or an empty string to ignore this.</param>
        /// <param name="OverwriteExistingCell">True to overwrite the existing cell value with the hyperlink display text. False otherwise.</param>
        /// <returns>True if successful. False otherwise.</returns>
        public bool InsertHyperlink(int RowIndex, int ColumnIndex, SLHyperlinkTypeValues HyperlinkType, string Address, string Display, string ToolTip, bool OverwriteExistingCell)
        {
            if (RowIndex < 1 || RowIndex > SLConstants.RowLimit)
            {
                return(false);
            }
            if (ColumnIndex < 1 || ColumnIndex > SLConstants.ColumnLimit)
            {
                return(false);
            }

            SLHyperlink hl = new SLHyperlink();

            hl.IsNew = true;

            hl.Reference = new SLCellPointRange(RowIndex, ColumnIndex, RowIndex, ColumnIndex);

            switch (HyperlinkType)
            {
            case SLHyperlinkTypeValues.EmailAddress:
                hl.IsExternal       = true;
                hl.HyperlinkUri     = string.Format("mailto:{0}", Address);
                hl.HyperlinkUriKind = UriKind.Absolute;
                break;

            case SLHyperlinkTypeValues.FilePath:
                hl.IsExternal   = true;
                hl.HyperlinkUri = Address;
                // assume if it starts with ../ or ./ it's a relative path.
                hl.HyperlinkUriKind = Address.StartsWith(".") ? UriKind.Relative : UriKind.Absolute;
                break;

            case SLHyperlinkTypeValues.InternalDocumentLink:
                hl.IsExternal = false;
                hl.Location   = Address;
                break;

            case SLHyperlinkTypeValues.Url:
                hl.IsExternal       = true;
                hl.HyperlinkUri     = Address;
                hl.HyperlinkUriKind = UriKind.Absolute;
                break;
            }

            if (Display == null)
            {
                hl.Display = Address;
            }
            else
            {
                if (Display.Length == 0)
                {
                    hl.Display = Address;
                }
                else
                {
                    hl.Display = Display;
                }
            }

            if (ToolTip != null && ToolTip.Length > 0)
            {
                hl.ToolTip = ToolTip;
            }

            SLCell  c;
            SLStyle style;

            if (slws.CellWarehouse.Exists(RowIndex, ColumnIndex))
            {
                c     = slws.CellWarehouse.Cells[RowIndex][ColumnIndex];
                style = new SLStyle();
                if (c.StyleIndex < listStyle.Count)
                {
                    style.FromHash(listStyle[(int)c.StyleIndex]);
                }
                else
                {
                    style.FromHash(listStyle[0]);
                }
                style.SetFontUnderline(UnderlineValues.Single);
                style.SetFontColor(SLThemeColorIndexValues.Hyperlink);
                c.StyleIndex = (uint)this.SaveToStylesheet(style.ToHash());

                if (OverwriteExistingCell)
                {
                    // in case there's a formula
                    c.CellFormula = null;
                    c.DataType    = CellValues.SharedString;
                    c.CellText    = this.DirectSaveToSharedStringTable(hl.Display).ToString(CultureInfo.InvariantCulture);
                }
                // else don't have to do anything

                slws.CellWarehouse.SetValue(RowIndex, ColumnIndex, c);
            }
            else
            {
                c = new SLCell();

                style = new SLStyle();
                style.FromHash(listStyle[0]);
                style.SetFontUnderline(UnderlineValues.Single);
                style.SetFontColor(SLThemeColorIndexValues.Hyperlink);
                c.StyleIndex = (uint)this.SaveToStylesheet(style.ToHash());

                c.DataType = CellValues.SharedString;
                c.CellText = this.DirectSaveToSharedStringTable(hl.Display).ToString(CultureInfo.InvariantCulture);
                slws.CellWarehouse.SetValue(RowIndex, ColumnIndex, c);
            }

            slws.Hyperlinks.Add(hl);

            return(true);
        }