Question

I’m trying to bind a LINQ query that has a Distinct() in it and bind it to a Telerik Grid (this is the Telerik grid still, haven’t converted to Kendo yet). I’ve tried adding AsQueryable() to it also, but still getting a “Specified method is not supported exception.”

My query looks like this:

var rewardTypes = (from type in _rewardTypeRepository.GetAll()
                           from vo in type.ValidOutlets
                           join ot in _outletRepository.GetAll()
                               on vo.Outlet.Id equals ot.Id
                           where userOutletIds.Contains(ot.Id)
                           select vo.RewardType).Distinct().AsQueryable();

Any ideas or guidance on this would be greatly appreciated.

Thank you,
Matt

Answer 1

Using .Distinct() or IQueryable<T> just lazy loads the collection of data, meaning it’s not actually enumerated yet.

Try converting it to a List<T>.

var rewardTypes = (from type in _rewardTypeRepository.GetAll()
                   from vo in type.ValidOutlets
                   join ot in _outletRepository.GetAll()
                       on vo.Outlet.Id equals ot.Id
                   where userOutletIds.Contains(ot.Id)
                   select vo.RewardType).ToList();

If you want to remain “light” and not enumerate every item in a potentially large collection, I suggest using the .Skip() and .Take() methods to paginate through results at your convenience. Both those methods work against an IQueryable<T> collection.