public XElement ToXML() { var xPublishInfo = new XElement(Fb2Const.fb2DefaultNamespace + PublishInfoElementName); if (BookTitle != null) { xPublishInfo.Add(BookTitle.ToXML(BookNameElementName)); } if (Publisher != null) { xPublishInfo.Add(Publisher.ToXML(PublisherElementName)); } if (City != null) { xPublishInfo.Add(City.ToXML(CityElementName)); } if (Year != null) { xPublishInfo.Add(new XElement(Fb2Const.fb2DefaultNamespace + YearElementName, Year.ToString())); } if (ISBN != null) { xPublishInfo.Add(ISBN.ToXML(ISBNElementName)); } foreach (SequenceType sec in ItemSequences) { xPublishInfo.Add(sec.ToXML()); } return xPublishInfo; }