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LINQ. Why full load only the first time?

I have an entity Contracts, ListKindWorks and KindWorks.
public partial class Contracts
{
public Contracts()
{
ListKindWorks = new HashSet<ListKindWorks>();
}
public int Id { get; set; }
...
public virtual ICollection<ListKindWorks> ListKindWorks { get; set; }
}
public partial class ListKindWorks
{
public int IdContract { get; set; }
public int IdKindWork { get; set; }
public virtual Contracts IdContractNavigation { get; set; }
public virtual KindWorks IdKindWorkNavigation { get; set; }
}
public partial class KindWorks
{
public KindWorks()
{
ListKindWorks = new HashSet<ListKindWorks>();
}
public int Id { get; set; }
public string Title { get; set; }
public virtual ICollection<ListKindWorks> ListKindWorks { get; set; }
}
And class Item
public class Item
{
public int Id { get; set; }
public string Value { get; set; }
}
I want to load related elements via method Load():
source = model.Contracts
.OrderByDescending(r => r.Id)
.Skip(Page * Size)
.Take(Size)
.Select(c => new ContractTableRow
{
IdContract = c.Id,
FullName = c.WorkerNavigation.FullName,
IdWorker = c.Worker,
...
// this code
KindWork = c.ListKindWorks
.Select(y => new Item
{ Id = y.IdKindWork, Value = y.IdKindWorkNavigation.Short })
.ToList(),
Subject = c.ListSubjects
.Select(y => new Item
{ Id = y.IdSubject, Value = y.IdSubjectNavigation.Short })
.ToList()
})
.ToList();
The first call of the method Load() (during load app) gives full elements. KindWork and Subject are not empty. But then when I change Page, KindWork and Subject are empty. The rest is always changing.
Why don't subsequent calls load this part?

Use variable source as IQueryable so every time you use .ToList() query will be executed against database so you will get your changed data.
IQueryable<Contracts> source = *...* // without .ToList()
This will save this as a query (without data, as it is not executed yet on db)
Every time you call .ToList() EF will execute on sql.
var smth = source.ToList();

I dont know what im doing wrong with my lambda expression, can someone correct me?

I'm using FrameworkEntity and have two classes:
public class InfoComplementarEmpresaModel
{
public int idempresa { get; set; }
[Key]
public string idcomplemento { get; set; }
public string idinformacao { get; set; }
public string conteudocomplemento { get; set; }
public string periodocomplemento { get; set; }
}
and
public class InfoComplementarModel
{
public int idlayout { get; set; }
[Key]
public int idinformacao { get; set; }
public string codigoinformacao { get; set; }
public string descricaoinformacao { get; set; }
public int tipoinformacao { get; set; }
}
The lambda join im trying to do is the following:
public List<string> GetTipoENomeDeInformacaoComplementarEmpresa(string idDaEmpresa)
{
List<string> listaDeTipos = new List<string>();
int idDaEmpresaNoFormatocerto = Convert.ToInt32(idDaEmpresa);
listaDeTipos.Add("Criar novo preenchimento de valores");
var nomesDeInformacoes = db.InformacoesComplementaresDaEmpresa
.Where(a => a.idempresa == idDaEmpresaNoFormatocerto)
.Join(db.InformacoesComplementaresDoLayout,
infocompempresa => new {infocompempresa.idinformacao},
infocomplayout => new {infocomplayout.idinformacao},
(ice, icl) => ice.idinformacao)
.ToList();
// some method that will put nomesDeInformacoes in listaDeTipos
return listaDeTipos;
}
The Join accuses "The type arguments for method Queryable.Join(IQueryable, IQueryable, Expression>, Expression>, Expression>) cannot be inferred from the usage. Try specifying the type arguments explicitly"

I FIGURED IT OUT
there were various problems:
idinformacao in InfoComplementarEmpresaModel was a string instead of a int
Then i discovered that ALL the anonymous names in the join must remain the same, resulting in:
var nomesDeInformacoes = db.InformacoesComplementaresDaEmpresa.Where(a => a.idempresa == idDaEmpresaNoFormatocerto)
.Join(db.InformacoesComplementaresDoLayout,
ice => ice.idinformacao ,
icl => icl.idinformacao ,
(ice, icl) => new { ice, icl } )
.Select(
//creating a class to accept the fields i want
})
.ToList();
This guy works, returning in the class im creating.

How to group by a list of objects and declare this list as an attribute of a viewmodel

Basically I have this class
public class Gasto
{
public int IdTienda { get; set; }
public int IdGasto { get; set; }
public System.DateTime Fecha { get; set; }
public string ConceptoDeGasto { get; set; }
public double Total { get; set; }
public string TipoDeGasto { get; set; }
public Nullable<int> IdVenta { get; set; }
public Nullable<System.DateTime> FechaVenta { get; set; }
public virtual Tienda Tienda { get; set; }
}
And I'm trying to build a ViewModelClass like this
public class CorteConVentas
{
// STILL NO ATRIBUTE -- THIS IS THE QUESTION
}
Here is the code for the controller where I will build a List of Gasto grouped by TipoDeGasto
var gastos = db.Gastos.Where(g => g.IdGasto >= corte.DesdeIdGasto && g.IdGasto <= corte.HastaIdGasto).ToList();
var GD = gastos.GroupBy(u => u.TipoDeGasto).Select(grp => new { TipoGasto = grp.Key, gastos = grp.ToList() } ).ToList();
As you can see the variable "GD" is a List of Strings (TipoGasto) with List of Gasto.
¿The issue (question) is this GD how can I declare it as an attribute of my viewModelClass?
I tried something like this for the ViewModel
public class CorteConVentas
{
public List<string, List<Gasto>> listaGastosAgrupada { get; set; }
}
But there is something wrong. The output of the error says:
Using the generic type List requires 1 type arguments
Here is the output after grouping by
Finally the solution as #Ziv Weissman said was not to use an anonymous type
So I created a class like this
public class CorteConVentas
{
public List<GastosAgrupados> listaGastosAgrupada { get; set; }
}
public class GastosAgrupados
{
public string TipoGasto { get; set; }
public List<Gasto> gastos { get; set;}
}
And then in the controller when creating the grouped list I did this
var gastos = db.Gastos.Where(g => g.IdGasto >= corte.DesdeIdGasto && g.IdGasto <= corte.HastaIdGasto).ToList();
var gd = gastos.GroupBy(u => u.TipoDeGasto).Select(grp => new GastosAgrupados { TipoGasto = grp.Key, gastos = grp.ToList()) } ).ToList();
Thanks to all for helping me.

You cannot declare a variable of anonymous type:
.Select(grp => new { TipoGasto = grp.Key, gastos = grp.ToList() } )
You must create another class which has these two props.
(or use a KeyValuePair)
Something like -
.Select(grp => new KeyValuePair<string,List<Gasto>> { Key = grp.Key, Value = grp.ToList() } )
Then you can create a strong typed prop.
public class CorteConVentas
{
List<KeyValuePair<string,List<Gasto>>> PropName {get; set;}
}

Simple answer, just look up GroupBy() in the docs, and see what it returns:
IEnumerable<IGrouping<TKey, TElement>>
which is your case would be:
public class CorteConVentas
{
public IEnumerable<IGrouping<string, Gasto>> listaGastosAgrupada { get; set; }
}
Update:
Didn't notice the select after the GroupBy(). Try this:
public class GrupoGastos // forgive my attempts at Spanish via Google Translate
{
public string TipoGasto {get; set;}
public List<Gasto> Gastos {get; set;}
}
then
var GD = gastos.GroupBy(u => u.TipoDeGasto)
.Select(grp => new GrupoGastos
{ TipoGasto = grp.Key, Gastos = grp.ToList() } )
.ToList();
and finally:
public class CorteConVentas
{
public List<GrupoGastos> listaGastosAgrupada { get; set; }
}

First, looks like you want a dictionary, not a list:
public class CorteConVentas
{
public Dictionary<string, List<Gasto>> dictaGastosAgrupada { get; set; }
}
Second, that select list with two columns is going to give you trouble because it comes out as an anonymous type, and you have no way to declare a dictionary that will contain it. Instead, just return the object:
var GD = gastos.GroupBy(u => u.TipoDeGasto).Select(grp);
So now you have GD which will let you enumerate over a list of grp objects. You can add them to your dictionary like this:
foreach (var grp in GD) dictaGastosAgrupada.Add(grp.Key, grp.ToList());

Entity Framework Select Query

I have the following classes:
public class Seller : Entity
{
public int SellerId { get; set; }
public string Name { get; set; }
public ICollection<InventoryItem> InventoryItems { get; set; }
}
public class InventoryItem : Entity
{
public int InventoryId { get; set; }
public int SellerId { get; set; }
public string SellerSku { get; set; }
public ICollection<SiteInventoryItem> SiteInventoryItems { get; set; }
}
public class SiteInventoryItem : Entity
{
public int Id { get; set; }
public int InventoryId { get; set; }
public SiteType Site { get; set; }
}
So a Seller has a collection of InventoryItem which in turn have a collection of SiteInventoryItem.
How do I get a Seller with a list of InventoryItems that have a list of SiteInventoryItems where the SiteType == SiteType.SiteName and the Seller.SellerId == 14?
The SiteType is an Enum and the db type is int.
I have tried the following and it compiles and runs, but the result is not what is expected:
var seller = repo.Query(
x => x.InventoryItems,
x => x.InventoryItems.Select(y => y.SiteInventoryItems)
).Select(x => new
{
Seller = x,
InventoryItems = x.InventoryItems,
SiteInventoryItems = x.InventoryItems.Select(y => new
{
InventoryItem = y,
SiteInventoryItems = y.SiteInventoryItems.Where(z => z.Site == SiteType.Amazon)
})
}).Where(x => x.Seller.SellerId == 14).First();

var seller = repo.Query()
.Select(x => new
{
Seller = x,
InventoryItems = x.InventoryItems.Select(y => new
{
InventoryItem = y,
SiteInventoryItems = y.SiteInventoryItems.Where(z => z.Site == SiteType.Amazon)
}).Where(y => y.SiteInventoryItems.Any())
}).Where(x => x.Seller.Id == 14).First();
I've restructured the result type a bit, because I think it makes more sense this way. Now you see that the result only returns Sellers that have InventoryItems that have SiteInventoryItems.
Note that I also removed the arguments for repo.Query(). I assume that they serve as Includes. But I also hope that repo.Query() returns an IQueryable, so that the Where clause will be translated into the generated SQL. If so, the Includes are useless, because you're already querying the included entities because they are part of the anonymous type.

how to assign collection of classes to a new viewmodel

I have this scenario:
I want to make a ViewModel with the property that I only want but my issue is with the Collections. So here's an example:
Main classes:
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<Order> Orders { get; set; }
// remove some code for brevity
}
public class Order
{
public int Id { get; set; }
public string ItemName { get; set; }
public int CustomerId { get; set; }
public virtual Customer Customer { get; set; }
// remove some code for brevity.
}
View Models:
public class OrderVM
{
public string ItemName { get; set; }
}
public class CustomerVM
{
public string Name { get; set; }
public ICollection<OrderVM> Orders { get; set; }
}
Then I tried something like this:
_customerService.Include(c => c.Orders)
.Select(x => new CustomerVM
{
Name = x.Name,
Orders = x.Orders.Select(order => new OrderVM { ItemName = order.ItemName }) // but it says cannot convert implicitly from IEnumerable to ICollection
}
)
In a nutshell, how can I populate CustomerVM's properties? I only want to select that I want. Any thoughts? Really stuck here.

Linq .Select() generates IEnumerable<T> but your property is ICollection<T>. You can append .ToList() to the query to generate List<T> which is ICollection<T>.
customerService.Include(c => c.Orders)
.Select(x => new CustomerVM
{
Name = x.Name,
Orders = x.Orders
.Select(order => new OrderVM { ItemName = order.ItemName }).ToList()
}
Alternatively, if you do not specifically need Orders to be ICollection, then you could change your property definition to
public IEnumerable<OrderVM> Orders { get; set; }

just use ToList() to convert IEnumerable to ICollection. Not tested but it should work
customerService.Include(c => c.Orders)
.Select(x => new CustomerVM
{
Name = x.Name,
Orders = x.Orders.Select(order => new OrderVM { ItemName = order.ItemName }).ToList()
}