SQL IN statement in Linq for NHibernate

I have this Lookup to group ResultId by Symbol. I have Linq query below but I cannot make SQL IN statement by using Contain() which is state by this post http://blog.wekeroad.com/2008/02/27/creating-in-queries-with-linq-to-sql

        // This will group ResultIds (Guid) by their symbol (string).
        var asd = ResultIdsAndSymbols.ToLookup(x => x.Symbol, y => y.ResultID);

        foreach (var qwe in asd)
        {
            var Numbers = (from t in S开发者_如何学JAVAession.Query<TableName>()
                         where qwe.Contains(t.ResultID)
                         select t.Number).ToList();
        }

Update:

After retrying this code and deep analyzing the error (System.InvalidCastException: Object must implement IConvertible), I got this informative error message: "Failed to convert parameter value from a Grouping to a Guid". qwe is a type of IGrouping<string, Guid> and it will become IEnumerable<Guid> which should not be a problem like we pass this into a List constructor or used in foreach statement. The exception thrown in System.Data.SqlClient. I think NHibernate simply pass the Grouping<TKey, TElement> into the sql parameter that cause the error. NHibernate should be designed to enumerate to any IEnumerable<T> and generate the SQL IN query just like how it does for List<T>.

The List<T>, Array[], Stack work well. So I change the code to this:

where qwe.ToList().Contains(t.ResultID)

Update: Issue reported: https://nhibernate.jira.com/browse/NH-2762

The NHibernate LINQ provider is limited when it comes to the IN clause. It seems to only work with collections where T is a simple type, e.g. List<string> or List<int>.

This works in NHibernate 3.1 (not tested in earlier versions):

var asd = ResultIdsAndSymbols.ToLookup(x => x.Symbol, y => y.ResultID);

foreach (var qwe in asd)
{
    List<int> list = qwe.ToList();
    var Numbers = (from t in Session.Query<TableName>()
                 where list.Contains(t.ResultID)
                 select t.Number).ToList();
}