CSMSL.IO.MzTab.MzTabPSM.GetValue C# (CSharp) Method

        public override string GetValue(string fieldName)
        {
            switch (fieldName)
            {
                case Fields.Sequence:
                    return string.IsNullOrEmpty(Sequence) ? MzTab.NullFieldText : Sequence;
                case Fields.ID:
                    return ID.ToString();
                case Fields.Accession:
                    return Accession;
                case Fields.Unique:
                    return Unique ? "1" : "0";
                case Fields.Database:
                    return string.IsNullOrEmpty(Database) ? MzTab.NullFieldText : Database;
                case Fields.DatabaseVersion:
                    return string.IsNullOrEmpty(DatabaseVersion) ? MzTab.NullFieldText : DatabaseVersion;
                case Fields.SearchEngine:
                    return SearchEngines == null ? MzTab.NullFieldText : string.Join("|", SearchEngines);
                case Fields.Reliability:
                    if (Reliability == MzTab.ReliabilityScore.NotSet)
                        return MzTab.NullFieldText;
                    return ((int) Reliability).ToString();
                case Fields.Modifications:
                    return string.IsNullOrEmpty(Modifications) ? MzTab.NullFieldText : Modifications;
                case Fields.RetentionTime:
                    return RetentionTime == null ? MzTab.NullFieldText : string.Join("|", RetentionTime);
                case Fields.Charge:
                    return Charge.ToString();
                case Fields.ExperimentalMZ:
                    return ExperimentalMZ.ToString();
                case Fields.TheoreticalMZ:
                    return TheoreticalMZ.ToString();
                case Fields.Uri:
                    return Uri == null ? MzTab.NullFieldText : Uri.ToString();
                case Fields.SpectraReference:
                    return string.IsNullOrEmpty(SpectraReference) ? MzTab.NullFieldText : SpectraReference;
                case Fields.PreviousAminoAcid:
                    return default(char).Equals(PreviousAminoAcid) ? "-" : PreviousAminoAcid.ToString();
                case Fields.FollowingAminoAcid:
                    return default(char).Equals(FollowingAminoAcid) ? "-" : FollowingAminoAcid.ToString();
                case Fields.StartResidue:
                    return StartResiduePosition.ToString();
                case Fields.EndResidue:
                    return EndResiduePosition.ToString();
            }

            if (fieldName.Contains("["))
            {
                string condensedFieldName;
                List<int> indices = MzTab.GetFieldIndicies(fieldName, out condensedFieldName);

                if (condensedFieldName == Fields.SearchEngineScore)
                {
                    return GetListValue(_searchEngineScores, indices[0]);
                }
            }

            if (fieldName.StartsWith(MzTab.OptionalColumnPrefix))
            {
                return GetOptionalData(fieldName);
            }

            throw new ArgumentException("Unexpected field name: " + fieldName);
        }