Opc.Ua.NumericRange.Validate C# (CSharp) Method

        public static ServiceResult Validate(string textToParse, out NumericRange range)
        {
            range = NumericRange.Empty;

            if (String.IsNullOrEmpty(textToParse))
            {
                return ServiceResult.Good;
            }

            // check for multidimensional ranges.
            int index = textToParse.IndexOf(',');

            if (index >= 0)
            {
                int start = 0;
                List<NumericRange> subranges = new List<NumericRange>();

                for (int ii = 0; ii < textToParse.Length; ii++)
                {
                    char ch = textToParse[ii];

                    if (ch == ',' || ii == textToParse.Length-1)
                    {
                        NumericRange subrange = new NumericRange();
                        string subtext = (ch == ',') ? textToParse.Substring(start, ii - start) : textToParse.Substring(start);
                        ServiceResult result = Validate(subtext, out subrange);

                        if (ServiceResult.IsBad(result))
                        {
                            return result;
                        }

                        subranges.Add(subrange);
                        start = ii+1;
                    }
                }

                // must have at least two entries.
                if (subranges.Count < 2)
                {
                    return StatusCodes.BadIndexRangeInvalid;
                }

                range.m_begin = subranges[0].Begin;
                range.m_end = subranges[0].End;
                range.m_subranges = subranges.ToArray();

                return ServiceResult.Good;
            }

            try
            {
                index = textToParse.IndexOf(':');

                if (index != -1)
                {
                    range.Begin = Convert.ToInt32(textToParse.Substring(0, index), CultureInfo.InvariantCulture);
                    range.End = Convert.ToInt32(textToParse.Substring(index + 1), CultureInfo.InvariantCulture);

                    if (range.End < 0)
                    {
                        return ServiceResult.Create(
                            StatusCodes.BadIndexRangeInvalid,
                            "NumericRange does not have a valid end index ({0}).",
                            range.End);
                    }

                    if (range.Begin >= range.End)
                    {
                        return ServiceResult.Create(
                            StatusCodes.BadIndexRangeInvalid,
                            "NumericRange does not have a start index that is less than the end index ({0}).",
                            range);
                    }
                }
                else
                {
                    range.Begin = Convert.ToInt32(textToParse, CultureInfo.InvariantCulture);
                    range.End   = -1;
                }                 

                if (range.Begin < 0)
                {
                    return ServiceResult.Create(
                        StatusCodes.BadIndexRangeInvalid,
                        "NumericRange does not have a valid start index ({0}).",
                        range.Begin);
                }
            }
            catch (Exception e)
            {
                return ServiceResult.Create(
                    e,
                    StatusCodes.BadIndexRangeInvalid,
                    "NumericRange cannot be parsed ({0}).", 
                    textToParse);
            }

           return ServiceResult.Good;
        }