using System; using System.Linq; using System.Collections; using System.Collections.Generic; using System.Xml; using System.Xml.Linq; public class MainClass { public static void Main() { XProcessingInstruction procInst; XDocument xDocument = new XDocument( new XElement("Books"), procInst = new XProcessingInstruction("Book", "out-of-print")); Console.WriteLine(xDocument); procInst.Target = "BookContactManager"; procInst.Data = "update"; Console.WriteLine(xDocument); } }