DataSource Controls :: Validate Results Of A Query?

I am trying to find out if there are records in a table

based on the results of the query.

I have this that is not working

The query works but the problem is validating the resutls

MembershipUser myUser = Membership.GetUser();
Guid userIdPosts = (Guid)myUser.ProviderUserKey;
int currentThreadid = Convert.ToInt32(Request.QueryString["Threadid"]);
var query = from t in context.TrackLists
where t.UserId == userIdPosts && t.ThreadID == currentThreadid
select new { t.UserId, t.ThreadID };
foreach (var results in query)
{
Guid queryUserID = results.UserId;
}
if (queryUserID == null)
{
}