Add first to XDocument in CSharp

using System;/*from ww  w.j a v a  2s.co m*/
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Xml;
using System.Xml.Linq;
using System.IO;

public class MainClass{

   public static void Main(string[] args){   
      XDocument NewDoc = new XDocument(new XDeclaration("1.0", "utf-8", "yes"),
            new XElement("Root", "MyDoc"));  
      NewDoc.AddFirst(new XDocumentType(
               "MyDocType", "MyPubID", 
               "MySysID", "ThisInternalSubset"));
  
      Console.WriteLine(NewDoc);
   }
}