How to convert (serialize) DataTable to XML string using C# .Net

Ok I got it. I have done it with the XML Parser. Here is my code:

[WebMethod]
        public string GetDropDownItems()
        {
            JavaScriptSerializer Serializer = new JavaScriptSerializer(); //not working with DataTable


            DataTable dt = new DataTable();
            dt.Columns.Add("ID", typeof(string));
            dt.Columns.Add("Name", typeof(string));

            dt.Rows.Add("1","A");
            dt.Rows.Add("2", "B");
            dt.Rows.Add("3", "C");

            return SerializeTableToString(dt);
            //return Serializer.Serialize(dt);
        }

        public static string SerializeTableToString(DataTable table)
        {
            if (table == null)
            {
                return null;
            }
            else
            {
                using (var sw = new StringWriter())
                using (var tw = new XmlTextWriter(sw))
                {
                    // Must set name for serialization to succeed.
                    table.TableName = @"MyTable";

                    tw.Formatting = Formatting.Indented;

                    tw.WriteStartDocument();
                    tw.WriteStartElement(@"data");

                    ((IXmlSerializable)table).WriteXml(tw);

                    tw.WriteEndElement();
                    tw.WriteEndDocument();

                    // --

                    tw.Flush();
                    tw.Close();
                    sw.Flush();

                    return sw.ToString();
                }
            }
        }

JavaScirpt:

function onDataSucceed(data, context) {
    alert(data);
    alert(data.length);

    var doctorsDropDown = document.getElementById('DropDown');

    if (window.DOMParser) {
        parser = new DOMParser();
        xmlDoc = parser.parseFromString(data, "text/xml");
    }
    else // Internet Explorer
    {
        xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
        xmlDoc.async = false;
        xmlDoc.loadXML(data);
    }

    alert(xmlDoc);
    alert(xmlDoc.getElementsByTagName("ID")[0].childNodes[0].nodeValue);

    var x = xmlDoc.getElementsByTagName("MyTable");
    for (i = 0; i < x.length; i++) {
        doctorsDropDown.options[doctorsDropDown.options.length] = new Option(x[i].getElementsByTagName("Name")[0].childNodes[0].nodeValue, x[i].getElementsByTagName("ID")[0].childNodes[0].nodeValue);
    }

Thanks for giving me your precious time. :)