序列化 对象 不需要创建文件的方法？

UserProfile profile = new UserProfile();

XmlSerializer serializer = new XmlSerializer(typeof(UserProfile));
MemoryStream ms = new MemoryStream();
using(TextWriter w = new StreamWriter( ms,System.Text.Encoding.UTF8 ))
{
serializer.Serialize(ms,profile);
}

string xml=System.Text.Encoding.UTF8.GetString(ms.ToArray());

XmlSerializer serializer = new XmlSerializer(typeof(ListItems));
XmlDocument doc = new XmlDocument();
const string root = @"<?xml version=""1.0""?>";
string xmlContent = root + HttpUtility.HtmlDecode(strExtend);
doc.LoadXml(xmlContent);
System.IO.MemoryStream stream = new System.IO.MemoryStream();
doc.Save(stream);
stream.Seek(0, SeekOrigin.Begin);
XmlSerializerNamespaces xmlns = new XmlSerializerNamespaces();
xmlns.Add(String.Empty, String.Empty);
ListItems m_ItemList = serializer.Deserialize(stream) as ListItems;

XmlSerializer serializer = new XmlSerializer(typeof(List<Option>));
string strContent = myRow["Options"].ToString();
XmlDocument doc = new XmlDocument();
doc.LoadXml(strContent.TrimEnd('？'));
System.IO.MemoryStream stream = new System.IO.MemoryStream();
doc.Save(stream);
stream.Seek(0, SeekOrigin.Begin);

List<Option> myList = serializer.Deserialize(stream) as List<Option>;