How can I use be generic to result of linq query? - linq

Question

Be first, my English is not very good. So I am sorry about that. :)
My question as the title. I have two tables on my database:
Siniflar (SinifId, SinifAdi, Kapasite, OgretmenId)
Ogretmenler (OgretmenId, Ad, Soyad, Brans)
Query:
var siniflar = (from s in db.Siniflar
join o in db.Ogretmenler
on s.OgretmenId equals o.OgretmenId
select new { s.SinifId, s.SinifAdi, s.Kapasite, o.Ad }).ToList();
I want to use the result of the query as a generic, like this:
public List<Siniflar> SiniflariListele()
{
var siniflar = (from s in db.Siniflar
join o in db.Ogretmenler
on s.OgretmenId equals o.OgretmenId
select new { s.SinifId, s.SinifAdi, s.Kapasite, o.Ad }).ToList();
return siniflar;
}
But I get an error. Because the result is anonymous types.
Error: Cannot implicitly convert type System.Collections.Generic.List<AnonymousType#1> to System.Collections.Generic.List<Entity.Siniflar>
How Can I use be generic result. What Can I do for that?
I changed question:
Class:
public class RSiniflar
{
public int SinifId { get; set; }
public string SinifAdi { get; set; }
public int Kapasite { get; set; }
public string OgretmenAdiSoyadi { get; set; }
}
Metod:
public List<RSiniflar> SiniflariListele()
{
List<RSiniflar> siniflar = (from s in db.Siniflar
join o in db.Ogretmenler
on s.OgretmenId equals o.OgretmenId
select new RSiniflar
{
SinifId = s.SinifId,
SinifAdi = s.SinifAdi,
Kapasite = s.Kapasite,
OgretmenAdiSoyadi = o.Ad + ' ' + o.Soyad
}).ToList();
return siniflar;
}
But now error to query: Unable to create a constant value of type 'System.Object'. Only primitive types or enumeration types are supported in this context.
I think, there are a problem on my query... I get an error same when query to var type...

Answer 1

You can return typed list, but you can't return a list of anonymous type. So you need to create a class which will handle your results:
public class A
{
public int SinifId { get; set; }
public int SiniAdi { get; set; }
public int Kapasite { get; set; }
public int Ad { get; set; }
}
And then use it in your query, instead of anonymous objects:
public List<A> SiniflariListele()
{
var siniflar = (from s in db.Siniflar
join o in db.Ogretmenler
on s.OgretmenId equals o.OgretmenId
select new A {
SinifId = s.SinifId,
SinifAdi = s.SinifAdi,
Kapasite = s.Kapasite,
Ad = o.Ad
}).ToList();
return siniflar;
}
You could do the same with an existing class (e.g. Siniflar), but you have to be sure that this class has all necessary properties.

Answer 2

Rather than using new { property1, property2 }, create new Siniflar's in your select.
E.g.
select new Siniflar() {
SinifId = s.SinifId,
SinifAdi = s.SinifAdi,
Kapasite = s.Kapasite }).ToList()
Note: as lazyberezovsky mentioned, your mapping seems to be flawed, as Siniflar does not contain the property Ad.