如何使用xmlReader.create获取XML属性?

我正在使用xmlReader.create从RSS XML文件中检索数据。然后我将这些数据放入数据集中,并将其绑定到ListView:

XmlReader xmlReader = XmlReader.Create(this.RssUrl);
XmlDataDocument xdoc = new XmlDataDocument();
xdoc.DataSet.ReadXml(xmlReader, XmlReadMode.InferSchema);

问题是,我试图获取的字段之一位于属性中。如何从下面的“media:thumbnail”中获取“url”属性?

<item> 
  <title>Some Title</title> 
  <description>Content goes here...</description> 
  <link>http://www.mydomain.com?id=439</link> 
  <guid>453252362</guid> 
  <pubDate>Sat, 21 Aug 2010 11:00:00 GMT</pubDate> 
  <media:thumbnail url="http://www.mydomain.com/catalog/1111tn.jpg" /> 
  <media:content url="http://www.mydomain.com/catalog/1111.jpg" /> 
</item> 

我是这样绑定它的,但是media:thumbnail显然是空的,因为我需要通过以下方式获取属性:

void singleItem_DataBinding(object sender, System.EventArgs e)
{
    Label singleItem = (Label)sender;
    singleItem.Text = String.Format(@"                    
        <div class=""rlvI content"">
            <div class=""image"">
                <a href=""{0}""><img src=""{1}"" alt=""{2}""></a>
            </div>
            <p>
                <span class=""title"">{2}</span><br />
                {3}
            </p>
        </div>",
        ((singleItem.NamingContainer as RadListViewDataItem).DataItem as DataRowView)["link"],
        ((singleItem.NamingContainer as RadListViewDataItem).DataItem as DataRowView)["media:thumbnail"],
        ((singleItem.NamingContainer as RadListViewDataItem).DataItem as DataRowView)["title"],
        ((singleItem.NamingContainer as RadListViewDataItem).DataItem as DataRowView)["description"]);
}

有人能帮忙吗?