using System;
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.Linq;
public class MainClass
{
public static void Main()
{
XNamespace ns = "A";
XElement root = new XElement(ns + "employee",
new XElement(ns + "firstname","aaa"),
new XElement(ns + "lastname","bbb")
);
root.SetAttributeValue("xmlns", ns);
//root.SetAttributeValue(XNamespace.Xmlns + "your value", ns);
Console.WriteLine(root.ToString());
}
}