关于XMLREADER的问题

XML文档:
<?xml version="1.0" encoding="utf-8" ?>
<films>
  <directors>
    <directors_id>1</directors_id>
    <name>hl</name>
    <movies>
      <movies_id>hl1</movies_id>
      <title>yellowroad</title>
      <year>1982</year>
    </movies>
    <movies>
      <movies_id>hl2</movies_id>
      <title>rain</title>
      <year>1983</year>
    </movies>
    <directors_id>2</directors_id>
    <name>tcx</name>
    <movies>
      <movies_id>tcx1</movies_id>
      <title>stairs</title>
      <year>2006</year>
    </movies>
  </directors>
</films>功能部分
protected void Page_Load(object sender, EventArgs e)
    {
        
        XmlDocument xd = new XmlDocument();
        xd.Load(@"G:\wsn2005\WEB\cs.xml");
        XmlReaderSettings xrs = new XmlReaderSettings();
        xrs.ConformanceLevel = ConformanceLevel.Auto;
        xrs.IgnoreWhitespace = true;
        xrs.IgnoreComments = true;
        XmlNodeReader xnr = new XmlNodeReader(xd);
        XmlReader xr = XmlReader.Create(xnr,xrs);
        while(xr.Read())
        {
            //this.Label1.Text = this.Label1.Text + xr.Value;
          //到这时都是执行的,就是下面就不执行了,因为我把上面去掉//后,可以返回值,下面不执行了不知道是为什么            
            if(xr.NodeType == XmlNodeType.Element)
            {
                this.Label1.Text = this.Label1.Text+xr.Value;
                if (xr.Name == "title")
               {
                this.Label1.Text = this.Label1.Text + xr.Value;
                TreeNode tn = new TreeNode(xr.Value);
                this.TreeView1.Nodes.Add(tn);
               }  
            }
        }
    }在if(xr.NodeType == XmlNodeType.Element)
开始就不执行了不知道是为什么,请大家解决一下