我如何从C＃中的波纹管XML中获取价值

当我尝试使用价值代码时 像这样

string xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>
<UserMLogin xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns=\"http://tempuri.org/\"> 
<Code>1</Code>
<Message>success</Message>
<Name>athil</Name>  
</UserMLogin>";

XmlDocument doc = new XmlDocument();
doc.LoadXml(xml.ToString());
XmlNodeList nodes = doc.DocumentElement.SelectNodes("/Code");

我无法读取值

<?xml version="1.0" encoding="utf-8"?><UserMLogin xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://tempuri.org/">  <Code>1</Code>  <Message>success</Message>  <Name>athil</Name></UserMLogin>