public IList<XPathNavigator> DocOrderDistinct(IList<XPathNavigator> seq) {
if (seq.Count <= 1)
return seq;
XmlQueryNodeSequence nodeSeq = (XmlQueryNodeSequence) seq;
if (nodeSeq == null)
nodeSeq = new XmlQueryNodeSequence(seq);
return nodeSeq.DocOrderDistinct(this.docOrderCmp);
}