I made a moles in for testing my repository class and it works when I put DefaultIfEmpty(new Drivers()) but when I run the program, I get this error: Unsupported overload used for query operator 'DefaultIfEmpty'.
But when I put it back to DefaultIfEmpty(), it works fine but my*strong text* moles test now returns a null value.. Here is my code:
var result = from p in this.context.AirPositions
join a in this.context.Airplane p.airplane_id equals a.id
join s in this.context.Status on p.status_id equals s.id
join dp in this.context.DriversPositions on p.id equals dp.position_id into dpJoin
from ds in dpJoin.DefaultIfEmpty(new DriversPosition())
join d in this.context.Drivers on ds.driver_id equals d.id into dsJoin
from drs in dsJoin.DefaultIfEmpty(new Driver())
orderby p.timesent descending
select new PositionViewModel()
{ ... };
It seems there is a problem with code that runs with Linq-to-Sql and Linq-to-Object.
I solved it with the following:
var result = from p in this.context.AirPositions
join a in this.context.Airplane on p.asset_id equals a.id
let driver = (from dd in this.context.DriversPositions.Where(u => u.position_id == p.id)
join d in this.context.Drivers on dd.driver_id equals d.id
select d).FirstOrDefault()
orderby p.timesent descending
select new PositionViewModel() {...}
Hope this helps other people :)