Can't read xml through XPathNavigator

Here is my code, I don't know why I can't read the data through XPathNavigator. But it was well before I add namespace and schema.

            XmlReaderSettings settings = new XmlReaderSettings();
        settings.Schemas.Add("http://www.somewhere.com", schemaPath);
        settings.ValidationType = ValidationType.Schema;

        XmlReader reader = XmlReader.Create(xmlPath, settings);

        XPathDocument doc = new XPathDocument(reader);

        XPathNavigator nav = doc.CreateNavigator();
        XPathNodeIterator iter = nav.Select("/feeds/feed");

        while (iter.MoveNext())
        {
            XPathNavigator feed = iter.Current.SelectSingleNode("name");
            string name = feed.Value;
            feed = iter.Current.SelectSingleNode("url");
            string url = feed.Value;
            feed = iter.Current.SelectSingleNode("url/@ver");
            string version = feed.Value;
            Console.WriteLine(name + ":" + url + ":" + version);}

The XML:

<?xml version="1.0" encoding="utf-8"?>
<feeds xmlns="http://www.somewhere.com">
  <feed>
    <name>asdf</name>
    <url ver="1.0">http://blogs.msdn.com/asdf/rss.xml</url>
  </feed>
  <feed>
    <name>asdf 2</name>
    <url ver="2.0">http://blogs.msdn.com/asdf2/rss.xml</url>
  </feed>
</feeds>

and schema:

<?xml version="1.0" encoding="utf-8"?>
<xs:schema
  targetNamespace="http://www.somewhere.com"
  elementFormDefault="qualified"
  xmlns="http://www.somewhere.com"
  xmlns:mstns="http://www.somewhere.com"
  xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="feeds">
    <xs:complexType >
      <xs:sequence >
        <xs:element na开发者_如何学Gome="feed" maxOccurs="unbounded">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="name" type="xs:string"/>
              <xs:element name="url">
                <xs:complexType >
                  <xs:simpleContent>
                    <xs:extension base="xs:string">
                      <xs:attribute name="ver" type="xs:string" />
                    </xs:extension>
                  </xs:simpleContent>
                </xs:complexType>
              </xs:element>
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

You can add the namespace to the XPath:

var xPathNavigator = doc .CreateNavigator();
var xmlNamespaceManager = new XmlNamespaceManager(xPathNavigator.NameTable);
xmlNamespaceManager.AddNamespace("x", "http://www.somewhere.com");
xPathNavigator.Select("/x:feeds/x:feed", xmlNamespaceManager);