/// <summary>
        ///
        /// </summary>
        /// <param name="writer"></param>
        public override void WriteXml(System.Xml.XmlWriter writer)
        {
            if (Values == null)
            {
                return;
            }

            int itemsCount = Values.Count;

            writer.WriteAttributeString(RedmineKeys.ID, Id.ToString(System.Globalization.CultureInfo.InvariantCulture));
            if (itemsCount > 1)
            {
                writer.WriteArrayStringElement(Values, RedmineKeys.VALUE, GetValue);
            }
            else
            {
                writer.WriteElementString(RedmineKeys.VALUE, itemsCount > 0 ? Values[0].Info : null);
            }
        }