self join Lambda query in Entity Framework

Question

my code is

    var model = dt.FishEventScheduleVaccination
            .Join(
                dt.FishEventSchedule,
                vaccination => vaccination.ScheduleId,
                schedule => schedule.ScheduleId,
                (vaccination, schedule) => new { vaccination, schedule }
            )
            .Select(q=>new {
                q.vaccination,
                q.schedule
            })
            .Where(w=>w.schedule.Start>DateTime.Now).ToList();
        var rtn=new List<FishEventScheduleVaccination>();
        foreach (var m in model) {
            var item = m.vaccination;
            item.FishEventSchedule = m.schedule;
            rtn.Add(item);
        }

i want do with only lambda query, not foreach. how can i do? Is it possible?

You can use the .ForEach(x => {...}) method, but this results in a loop, too. If you need a loop. you need a loop. — Marco
– Marco, Commented Nov 10, 2015 at 9:19
Since you are mutating the items, this is no more a query, hence do it with a loop or whatever is appropriate. — Ivan Stoev
– Ivan Stoev, Commented Nov 10, 2015 at 9:29

haim770 · Accepted Answer · 2015-11-10 09:46:16Z

1

Try this instead:

dt.FishEventScheduleVaccination
    .Join(dt.FishEventSchedule,
          vaccination => vaccination.ScheduleId,
          schedule => schedule.ScheduleId,
          (vaccination, schedule) => new { vaccination, schedule })
    .Where(w => w.schedule.Start > DateTime.Now)
    .AsEnumerable()
    .Select(q => { q.vaccination.FishEventSchedule = q.schedule; return q.vaccination; })
    .ToList();

answered Nov 10, 2015 at 9:46

haim770

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Comments

Rob · Accepted Answer · 2015-11-10 09:46:26Z

1

from r in Entities.tbl join q in Entities.tbl on r.Id equals q.Id2 select new
{
    Id = r.Column + " " + r.Column, Data = q.Column + " " + q.Column 
};

I think this should solve your Query

OR

you can also try something like this:

db.DTOPageSets.Join(db.DTOPageSets
                    .AsEnumerable(), a => a.ContentPageID, b => b.CategoryID, (a, b) => a);

edited Nov 10, 2015 at 9:46

Rob♦

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answered Nov 10, 2015 at 9:22

Arijit Mukherjee

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