I find a solution here it is
XDocument doc = new XDocument();
XElement ele = new XElement("Element", new XElement("ID", TxtID.Text), new XElement("Name", TxtName.Text), new XElement("City", DdlCity.SelectedItem.Text));
cmd = new SqlCommand("XmlDataModifications", con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("@XMLdata", SqlDbType.Xml);
cmd.Parameters["@XMLdata"].Value = ele.ToString();
con.Open();
cmd.ExecuteNonQuery();
con.Close();