C# - Get An XML Attribute With XmlReader.Create?

I am using XmlReader.Create to retrieve data from an RSS xml file. Then I am putting this data into a DataSet and binding it to a ListView:

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

The problem is that one of the fields I am trying to get is in an attribute. How do I get the "url" attribute from "media:thumbnail" below?

<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>

I am bind it like this, but the media:thumbnail is null obviously because I need to get the attribute some how:

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"]);
}