XmlSerializer序列化对象时，如何设置xmlns=""

Question

        // 需要序列化的对象
    [XmlRoot(ElementName ="interface",Namespace ="")]
    public class Root
    {
        [XmlAttribute("schemaLocation",Namespace= XmlSchema.InstanceNamespace)]
        public string xsiSchemaLocation = "http://wwww.test.com";
        [XmlAttribute(AttributeName ="version")]
        public string Version { get; set; }
        }

        // 序列化方法
                        MemoryStream ms = new MemoryStream();
            StreamWriter sw = new StreamWriter(ms, Encoding.UTF8);
            XmlSerializer serializer = new XmlSerializer(typeof(Root));

            serializer.Serialize(sw,root);
            result = Encoding.UTF8.GetString(ms.GetBuffer());
            sw.Close();
            ms.Close();

        //序列化结果
        <?xml version="1.0" encoding="utf-8"?>
<interface xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://wwww.test.com" version="测试版本">
  <globalInfo>
    <InterfaceCode>2</InterfaceCode>
    </globalInfo>
    </interface>

我想要在中显示，该如何设置？