NHibernate GroupBy error - linq

Question

Good morning
I am pulling my hair on a simple linq query used for building a json:
JsonSerializer serializer = new JsonSerializer();
JObject myJSON = new JObject();
var result = new
{
test = from e in myTable
group e by new { e.col1, e.col2 } into g
select new
{
Code = g.Key.col1,
Name = g.Key.col2,
data = from e in myTable
where e.col1== g.Key.col1
select new
{
myField= e.field1
}
}
};
myJSON = JObject.FromObject(result, serializer);
When i tried that i got a:
System.NotImplementedException: The method or operation is not implemented.
at NHibernate.Linq.GroupBy.NonAggregatingGroupByRewriter.FlattenSubQuery(SubQueryExpression subQueryExpression, QueryModel queryModel).
My linq query does not look that complicated but i have exhausted all my attempts.
Your lights on that would be welcome.
Thanks
Sylvain

Answer 1

OK, finally found it. Just had to do the following:
JsonSerializer serializer = new JsonSerializer();
JObject myJSON = new JObject();
var result = new
{
test = from e in myTable.ToList()
group e by new { e.col1, e.col2 } into g
select new
{
Code = g.Key.col1,
Name = g.Key.col2,
data = from e in myTable
where e.col1== g.Key.col1
select new
{
myField= e.field1
}
}
};
myJSON = JObject.FromObject(result, serializer);
with a .ToList() on the first query.
Sylvain