System.Xml.Xsl.XsltOld.NumberAction.Format C# (CSharp) Method

        private static string Format(ArrayList numberlist, List<FormatInfo> tokens, string lang, string letter, string groupingSep, string groupingSize) {
            StringBuilder result = new StringBuilder();
            int cFormats = 0;
            if (tokens != null) {
                cFormats = tokens.Count;
            }

            NumberingFormat numberingFormat = new NumberingFormat();
            if (groupingSize != null) {
                try {
                    numberingFormat.setGroupingSize(Convert.ToInt32(groupingSize, CultureInfo.InvariantCulture));
                }
                catch (System.FormatException) {}
                catch (System.OverflowException) {}
            }
            if (groupingSep != null) {
                if (groupingSep.Length > 1) {
                }
                numberingFormat.setGroupingSeparator(groupingSep);
            }
            if (0 < cFormats) {
                FormatInfo prefix = tokens[0];
                Debug.Assert(prefix == null || prefix.isSeparator);
                FormatInfo sufix = null;
                if (cFormats % 2 == 1) {
                    sufix = tokens[cFormats - 1];
                    cFormats --;
                }
                FormatInfo periodicSeparator = 2 < cFormats ? tokens[cFormats - 2] : DefaultSeparator;
                FormatInfo periodicFormat    = 0 < cFormats ? tokens[cFormats - 1] : DefaultFormat   ;
                if (prefix != null) {
                    result.Append(prefix.formatString);
                }
                int numberlistCount = numberlist.Count;
                for(int i = 0; i < numberlistCount; i++ ) {
                    int formatIndex   = i * 2;
                    bool haveFormat = formatIndex < cFormats;
                    if (0 < i) {
                        FormatInfo thisSeparator = haveFormat ? tokens[formatIndex + 0] : periodicSeparator;
                        Debug.Assert(thisSeparator.isSeparator);
                        result.Append(thisSeparator.formatString);
                    }

                    FormatInfo thisFormat = haveFormat ? tokens[formatIndex + 1] : periodicFormat;
                    Debug.Assert(!thisFormat.isSeparator);

                    //numberingFormat.setletter(this.letter);
                    //numberingFormat.setLang(this.lang);

                    numberingFormat.setNumberingType(thisFormat.numSequence);
                    numberingFormat.setMinLen(thisFormat.length);
                    result.Append(numberingFormat.FormatItem(numberlist[i]));
                }

                if (sufix != null) {
                    result.Append(sufix.formatString);
                }
            }
            else {
                numberingFormat.setNumberingType(NumberingSequence.Arabic);
                for (int i = 0; i < numberlist.Count; i++) {
                    if (i != 0) {
                        result.Append(".");
                    }
                    result.Append(numberingFormat.FormatItem(numberlist[i]));
                }
            }
            return result.ToString();
        }