How to Read XML String and Create XML File in Asp.net

SqlCommand cmd = new SqlCommand("Select top 10 * from TblAppointment", con);
        con.Open();
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);

        XmlDocument doc = new XmlDocument();

        foreach (var XML in ds.Tables[0].AsEnumerable())
        {
            doc.LoadXml(XML.Field<string>("AppointmentTransXml"));

            doc.Save(Server.MapPath("XML") + "//" + XML.Field<string>("Patientname") + ".xml");
        }

XML in LINQ ( Get Values from XML Using LINQ )

public
{
WeatherData GetCityTemprature(string city)XElement xe = XElement.Load(@".\WeatherForecast\City.xml");

var query = from xElem in xe.Elements("City")
where xElem.Element("Name").Value == city

select new WeatherData{
City = (string)xElem.Element("Name"),
State = (string)xElem.Element("State"),
MaxTemprature = Convert.ToDouble(xElem.Element("MaxTemp").Value),
MinTemprature = Convert.ToDouble(xElem.Element("MinTemp").Value),
};

}

WeatherData wd = query.First();return wd;