Question

The class “PaginatedReport” has two members :

int TotalResults;  
IList<Report> Reports; 

I try to populate an instance of this class using this query :

var reports = (from r in _db.Report
               where r.res_id == status
               group r by r.res_id into g
               select new PaginatedReport
               {
                   TotalResults = g.Count(),
                   Reports = g.OrderBy(x =>x.res_id).Skip(start).Take(nb).ToList()
               });

How can I correct the query to avoid the following error :
Linq to entitites do not recognize the method “System.Collections.Generic.List1[DAL.Report]
ToList[Report](System.Collections.Generic.IEnumerable1[DAL.Report])”, and this method cannot be translated into a store.

Answer 1

You need to perform the last step (a Select returning an anonymous type) locally, rather than having the LINQ provider try and translate it into (presumably) SQL. Something like:

var reports = from g in (from r in _db.Report
                         where r.res_id == status
                         group r by r.res_id).AsEnumerable()
              select new PaginatedReport {
               TotalResults = g.Count(),
               Reports = g.OrderBy(x =>x.res_id).Skip(start).Take(nb).ToList()
              };

(and you don’t need parentheses around the whole expression).