How to generate XML in asp.net?

DataSet ds= new DataSet();
ds= GetDataSetFromDataBase();
ds.GetXML();

http://msdn.microsoft.com/en-us/library/system.data.dataset.getxml.aspx

using (XmlWriter writer = XmlWriter.Create("employees.xml"))
{
    writer.WriteStartDocument();
    writer.WriteStartElement("Employees"); // <-- Important root element
     writer.WriteElementString("ID","10");   
    writer.WriteEndElement();              // <-- Closes it
    writer.WriteEndDocument();
}

  public void createXML()
    {
        XmlDocument doc = new XmlDocument();
       

        string filename="c:\\sample.xml";
        XmlTextWriter tw=new XmlTextWriter(filename,null);//null represents  the Encoding Type//
        tw.Formatting=Formatting.Indented;  //for xml tags to be indented//
       
        //tw.WriteStartDocument();   //Indicates the starting of document (Required)//


        //tw.WriteStartElement("Employees");			
        //tw.WriteStartElement("Employee","Genius");
        //tw.WriteAttributeString("Name","krishnan");
        //tw.WriteElementString("Designation","Software Developer");
        //tw.WriteElementString("FullName","krishnan Lakshmipuram Narayanan");

        tw.WriteStartElement("Author");
        tw.WriteElementString("ID","1");
        tw.WriteElementString("SubmissionDate","1-1-08");
        tw.WriteElementString("Topic","test");
        tw.WriteElementString("Title","test");
        tw.WriteStartElement("Authors");
        tw.WriteStartElement("Author");
        tw.WriteElementString("Name","XYZ");
        tw.WriteElementString("Affiliation","ABC");
        tw.WriteEndElement();
        tw.WriteEndElement();
        tw.WriteElementString("Summary","Hi");
        tw.WriteElementString("Text","Hello");

        tw.WriteEndElement();        
        //tw.WriteEndDocument();			
        tw.Flush();
        tw.Close();

        StreamReader srXml = new StreamReader(filename);
        string xmlFile = srXml.ReadToEnd();

    }

 static void Main(string[] args)
        {
            Console.WriteLine("Enter Employee detail\n\n");
            Console.WriteLine("Enter ID:");
            string id = Console.ReadLine();
            Console.WriteLine("Enter NAME:");
            string name = Console.ReadLine();
            Console.WriteLine("Enter DEPARTMENT:");
            string dept = Console.ReadLine();
            Console.WriteLine("Enter DATE OF BIRTH:");
            Console.WriteLine("Enter DAY:");
            string dd = Console.ReadLine();
            Console.WriteLine("Enter MONTH:");
            string mm = Console.ReadLine();
            Console.WriteLine("Enter YEAR:");
            string yy = Console.ReadLine();

            //MyXmlWrite(id, name, dept, dd, mm, yy);

//            Console.WriteLine("XML File is generated");
            AppendXml( id, name,  dept,  dd,  mm, yy);

            MyReadXml();


            Console.ReadLine();

        }

 public static void MyReadXml()
        {
            FileStream fs = new FileStream("z:\\Employee.xml", FileMode.OpenOrCreate, FileAccess.Read);
            XmlTextReader xr = new XmlTextReader(fs);
            xr.WhitespaceHandling = WhitespaceHandling.None;
            while (xr.Read())
            {
                switch (xr.NodeType)
                {
                    case XmlNodeType.Element:
                        Console.WriteLine(xr.Name + ":-");
                        if (xr.HasAttributes)
                        {

                            while (xr.MoveToNextAttribute())
                            {
                                Console.WriteLine(xr.Name + ":-\t" + xr.Value);
                            }

                            xr.MoveToElement();
                        }
                        break;
                    case XmlNodeType.Text:
                        Console.WriteLine("\t" + xr.Value);
                        break;

                }
            }
            xr.Close();
            fs.Close();
        }