Linq To Xml Datasource For Grid View Is Not Working - The Grid Show No Rows

I'm getting some Xml back from a service. I would like it to be the datasource of a grid view on my aspx page. Here is a sample of the Xml

<?xml version="1.0" encoding="utf-16" ?>
<ArrayOfTripTollCompleteDC xmlns:xsi=[URL]"
xmlns:xsd=[URL]>
<TripTollCompleteDC>
<TripTollId>5</TripTollId>
<DMSLaneModeID xsi:nil="true" />
<HOVOnly>false</HOVOnly>
<CreateDateTime>2010-06-07T15:54:01.023</CreateDateTime>
<ConfigVTMSDelaySeconds>5</ConfigVTMSDelaySeconds>
</TripTollCompleteDC>

and here is my code that parses the xml and tries to bind the grid. What am I missing here?

var retVal = service.GetTripDetailsByTripID(tripId);
var xmlTrips = XDocument.Parse(retVal);
var tripTolls =
from t in xmlTrips.Elements("TripTollCompleteDC")
select new {
TripTollId = (int)t.Element("TripTollId")
, DMSLaneModeID = (int?)t.Element("DMSLaneModeID")
, HOVOnly = (bool)t.Element("HOVOnly")
, CreateDateTime = (DateTime)t.Element("CreateDateTime")
, ConfigVTMSDelaySeconds = (int)t.Element("ConfigVTMSDelaySeconds")
};
grdTripDetails.DataSource = tripTolls;
grdTripDetails.DataBind();

I realize these are anonymous types. Is that a problem? I have verified the service is returning the Xml as stated above. Can anyone out there point me in the right direction? Just for completeness, here is the grid markup <asp:GridView runat="server" ID="grdTripDetails" />