/// <summary>
/// выбор уникальных значений
/// </summary>
/// <param name="iter"></param>
/// <param name="xpath"></param>
/// <returns></returns>
public XPathNodeIterator distinct_values(XPathNodeIterator iter, string xpath)
{
var values = iter.OfType <XPathNavigator>().Select(_ => _.Evaluate(xpath).ToStr()).Distinct();
var xe = new XElement("x");
xe.Add(values.Select(_ => new XElement("v", _)));
var nav = xe.CreateNavigator();
return(nav.Select("//v"));
}
private static List <string> XPathToStrings(XPathNodeIterator iterator)
{
return(iterator.OfType <XPathNavigator>().Select(n => n.OuterXml).ToList());
}