C# Convert Object (or List of Object) to XML

I have a scenario where i need to have xml data from list of objects to send data in a generalized format through http.
This is a generic function by which we can convert a single object as well as a list of objects into xml, object can have list of child objects also.

Main Function :
public string ConvertObjectToXML<T>(T obj)
        {
            System.Xml.Serialization.XmlSerializer xsSubmit = new      System.Xml.Serialization.XmlSerializer(typeof(T));
            System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
            System.IO.StringWriter sww = new System.IO.StringWriter();
            System.Xml.XmlWriter writer = System.Xml.XmlWriter.Create(sww);
            xsSubmit.Serialize(writer, obj);
            var xml = sww.ToString(); // Your xml context.Response.Write(xml);
            return xml;
        }


Implementation Example :

Test Objects:
 public class Order
    {
        public string orderno { get; set; }
        public List<OrderDetails> lst { get; set; }
    }

    public class OrderDetails
    {
        public string itemname { get; set; }
        public string itemqty { get; set; }
    }

Execution to get result :
public string About()
        {
            OrderDetails orderDetail1 = new OrderDetails { itemname="s", itemqty="1" };
            OrderDetails orderDetail2 = new OrderDetails { itemname = "s2", itemqty = "2" };
            OrderDetails orderDetail3 = new OrderDetails { itemname = "s3", itemqty = "3" };

            List<OrderDetails> lstOrderDetails1 = new List<OrderDetails>();
            lstOrderDetails1.Add(orderDetail1);
            lstOrderDetails1.Add(orderDetail2);
            lstOrderDetails1.Add(orderDetail3);

            Order order1 = new Order();
            order1.orderno = "001";
            order1.lst = lstOrderDetails1;


            OrderDetails orderDetail4 = new OrderDetails { itemname = "s4", itemqty = "4" };
            OrderDetails orderDetail5 = new OrderDetails { itemname = "s5", itemqty = "5" };
            OrderDetails orderDetail6 = new OrderDetails { itemname = "s6", itemqty = "6" };

            List<OrderDetails> lstOrderDetails2 = new List<OrderDetails>();
            lstOrderDetails2.Add(orderDetail4);
            lstOrderDetails2.Add(orderDetail5);
            lstOrderDetails2.Add(orderDetail6);

            Order order2 = new Order();
            order2.orderno = "002";
            order2.lst = lstOrderDetails2;

            List<Order> lstorder = new List<Order>();
            lstorder.Add(order1);
            lstorder.Add(order2);

            string resultXml = ConvertObjectToXML<List<Order>>(lstorder);
            return resultXml;
        }