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The expression 'y.Cases' is invalid inside an 'Include' operation

I have one-to-many relationship database. DbSet Companies being "One" and DbSet Cases being "many". Here's my context and model classes:
Database Context
class CaseContext : DbContext
{
public DbSet<ParticipantCompany> Companies{ get; set; }
public DbSet<ParticipantPerson> Persons { get; set; }
public DbSet<LegalCase> Cases { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder options)
=> options.UseSqlite("Data Source=Clients.db");
}
ParticipantCompany class inherits from Participant Class.
public class ParticipantCompany : Participant
{
public ParticipantCompany():this(false, "","","","") { }
public ParticipantCompany (bool isclient) : this(isclient, "","","","") { }
public ParticipantCompany(bool isclient, string name, string address, string inncompany, string ogrn) : base(isclient, SubjectType.Company)
{
Name = name;
Address = address;
InnCompany = inncompany;
Ogrn = ogrn;
}
public string InnCompany { get; set; }
public string Ogrn { get; set; }
}
public abstract class Participant
{
public Participant(bool isclient, SubjectType Type, string name, string address)
{
SubjType = Type;
IsClient = isclient;
Name = name;
Address = address;
}
public Participant(bool isclient, SubjectType Type ) : this(isclient, Type, "","")
{
}
public int Id { get; set; }
public SubjectType SubjType { get; private set; }
public bool IsClient { get; set; }
public string Name { get; set; }
public string Address { get; set; }
public List<LegalCase> Cases = new List<LegalCase>();
}
LegalCase class represents "Many" in relationships
public class LegalCase
{
public LegalCase() : this("", CaseType.ArbGeneral){}
public LegalCase(string casefabula, CaseType casetype)
{
CaseFabula = casefabula;
CaseType = casetype;
}
public int Id { get; set; }
public string CaseFabula { get; set; }
public CaseType CaseType { get; set; }
//public ICaseParticipant Client { get; set; }
public int? CompanyId { get; set; }
public ParticipantCompany Company { get; set; }
public int? PersonId { get; set; }
public ParticipantPerson Person { get; set; }
}
Now here's the Query:
using(var db = new CaseContext())
{
var QClients = db.Companies
.Where(x => x.IsClient == true)
//Exception: The expression 'y.Cases' is
// invalid inside an 'Include' operation,
// since it does not represent a property
// access: 't => t.MyProperty'. etc
.Include(y => y.Cases)
.ToList();
}
I tried to explicitly cast y to ParticipantCompany since it's what the prompt of the exection seems to suggest:
To target navigations declared on derived types, use casting ('t => ((Derived)t).MyProperty') or the 'as' operator ('t => (t as Derived).MyProperty')
But it generates the same exception:
using(var db = new CaseContext())
{
var QClients = db.Companies
.Where(x => x.IsClient == true)
//Same exception
.Include(y => (y as ParticipantCompany).Cases)
.ToList();
}

Change Cases from being field to property as the exception suggests:
public List<LegalCase> Cases { get; set; } = new List<LegalCase>();
From the docs:
Each entity type in your model has a set of properties, which EF Core will read and write from the database. If you're using a relational database, entity properties map to table columns.
By convention, all public properties with a getter and a setter will be included in the model.

RavenDB query child collection polymorphism

I have a document in RavenDB that contains a child collection. The child collection contains the following base type.
public class Section
{
public string BackgroundColor { get; set; }
public string Description { get; set; }
public string DesktopBackgroundImageUrl { get; set; }
public DateTime? EndDate { get; set; }
public string MobileBackgroundImageUrl { get; set; }
public int SortOrder { get; set; }
public DateTime? StartDate { get; set; }
public string TextColor { get; set; }
public string Title { get; set; }
public SectionType Type { get; set; }
}
There are a few derived classes from this type, one of which being this.
public class OfferSection : Section
{
public IEnumerable<Merchant> Merchants { get; set; }
}
The problem I'm having is that I need to query this child collection and get the documents that contain the derived type and then query it's values.
This is where I've got to so far, however because it's using the base type, the Merchants property doesn't exist
public class Hubs_ByMerchantId : AbstractIndexCreationTask<Hub>
{
public Hubs_ByMerchantId()
{
Map = hubs => from hub in hubs
select new
{
Sections_Merchants_Id = hub.Sections.Where(x => x.Type == SectionType.Offer).SelectMany(x => x.Merchants.Select(y => y.Id))
};
}
}
Can anyone point me in the right direction?
Thanks

You can use .OfType<Type> to get what ypou want:
hub.Sections.OfType<OfferSection>().SelectMany(x => x.Merchants.Select(y => y.Id));

After a bit of messing about the way I got this to work was by casting it inside the select. This worked because we already have a type enum saved against the section so it's easy enough to do the cast.
public class Hubs_ByMerchantId : AbstractIndexCreationTask<Hub>
{
public Hubs_ByMerchantId()
{
Map = hubs => hubs.SelectMany(x => (IEnumerable<OfferSection>)x.Sections).Where(x => x.Type == SectionType.Offer).Select(x => new
{
Sections_Merchants_Id = x.Merchants.Select(y => y.Id)
});
}
}
This probably isn't the best solution but it was the only thing that worked

Map string to a property in collection

I am trying to solve seemingly trivial task. How to map string to a property of a collection? Bellow I show my current situation. I am trying to map the DeliveryType.UrlTemplate property of DeliveryNoteTableDto class to each PackageDto.UrlTemplate property. I am using AutoMapper. Currently I am getting error:
Custom configuration for members is only supported for top-level individual members on a type.
when performing the mapping. Any help?
classes
public class DeliveryNoteTableDto
{
public List<PackageDto> Packages { get; set; } = new List<PackageDto>();
public DeliveryTypeDto DeliveryType { get; set; }
}
public class PackageDto
{
public virtual string DeliveryKey { get; set; }
public virtual string UrlTemplate { get; set; }
}
public class DeliveryTypeDto
{
public virtual string Transporter { get; set; }
public virtual string UrlTemplate { get; set; }
}
mapping
map.ForMember(x => x.Packages.Select(p => p.UrlTemplate), opt => opt.MapFrom(x => x.DeliveryType.UrlTemplate));

Switch between configurations in AutoMapper

I have this situation:
// Core Business classes
public class Invoice
{
public Guid Id { get; protected set; }
public int Number { get; set; }
public IList<InvoiceItem> Items { get; protected set; }
}
public class InvoiceItem
{
public Guid Id { get; protected set; }
public string Product { get; set; }
public int Quantity { get; set; }
public decimal Price { get; set; }
}
// MVC Models
public class InvoiceModel
{
public Guid Id { get; set; }
public int Number { get; set; }
public IList<InvoiceItemModel> Items { get; set; }
}
public class InvoiceItemModel
{
public Guid Id { get; set; }
public string Product { get; set; }
public int Quantity { get; set; }
public decimal Price { get; set; }
}
The automapper configuration
public class MyProfile : Profile
{
protected override void Configure()
{
Mapper.CreateMap<Invoice, InvoiceModel>();
Mapper.CreateMap<InvoiceItem, InvoiceItemModel>();
}
}
Then when I want to pass a model to my view, for example to edit an Invoice object, I do:
...
var invoice = Repository.Get<Invoice>(id);
return View("Update", Mapper.Map<InvoiceModel>(invoice));
...
And then I can iterate the Items collection with InvoiceItemModels.
The issue is when I want to retrieve a bunch of Invoices, for example in an index.
...
var invoices = Repository.ListAll<Invoice>();
return View("Index", invoices.Select(Mapper.Map<InvoiceModel>).ToList());
...
I don't want the "Items" to be loaded. A better configuration for this case will be:
public class MyFlatProfile : Profile
{
protected override void Configure()
{
Mapper.CreateMap<Invoice, InvoiceModel>()
.ForMember(m => m.Items, opt => opt.Ignore());
Mapper.CreateMap<InvoiceItem, InvoiceItemModel>();
}
}
But I have no idea how to switch between "Profiles".
Is there a way to "pick" a particular configuration of mapping?

Unfortunately, you have to create separate Configuration objects, and create a separate MappingEngine for each.
First, declear a static class to hold the mappers
public static class MapperFactory
{
public static MappingEngine NormalMapper()
{
var normalConfig = new ConfigurationStore(new TypeMapFactory(), MapperRegistry.Mappers);
normalConfig.CreateMap<Invoice, InvoiceModel>();
normalConfig.CreateMap<InvoiceItem, InvoiceItemModel>();
var normalMapper = new MappingEngine(normalConfig);
return normalMapper;
}
public static MappingEngine FlatMapper()
{
var flatConfig = new ConfigurationStore(new TypeMapFactory(), MapperRegistry.Mappers);
flatConfig.CreateMap<Invoice, InvoiceModel>()
.ForMember(m => m.Items, opt => opt.Ignore());
flatConfig.CreateMap<InvoiceItem, InvoiceItemModel>();
var flatMapper = new MappingEngine(flatConfig);
return flatMapper;
}
}
Then you can call the MappingEngine to do the mapping (The syntax is the same as Mapper object).
return View("Update", MapperFactory.FlatMapper().Map<InvoiceModel>(invoice));
return View("Update", MapperFactory.NormalMapper().Map<InvoiceModel>(invoice));

Only return specific properties

I have developed my first API controlled in MVC4 and through the scaffolding I have got it to automatically output a list of items:
// GET api/ItemList
public IEnumerable<ItemOption> GetItemOptions()
{
var itemoptions = db.ItemOptions.Include(i => i.Item);
return itemoptions.AsEnumerable();
}
This shows all the item properties from my model:
public class ItemOption
{
public int ItemOptionId { get; set; }
public bool Active { get; set; }
public string Name { get; set; }
public string test1 { get; set; }
public double PriceNet { get; set; }
}
How can I specify specific fields I wish to be returned? For example, I just want the ItemOptionId, Active and Name to be returned.
I have tried adding additional includes, but this seems to be at an object level.

Try creating a new type to represent the properties you'd like to return:
public class ItemOptionResult
{
public int ItemOptionId { get; set; }
public bool Active { get; set; }
public string Name { get; set; }
}
And then projecting your ItemOption collection, like this:
// GET api/ItemList
public IEnumerable<ItemOptionResult> GetItemOptions()
{`enter code here`
var itemoptions =
db.ItemOptions
.Select(i =>
new ItemOptionResult
{
ItemOptionId = i.ItemOptionId,
Active = i.Active,
Name = i.Name
});
return itemoptions.AsEnumerable();
}

Try this :
var itemoptions = db.ItemOptions.Select(io => new ItemOption()
{
ItemOptionId = io.ItemOptionId,
Active = io.Active ,
Name = io.Name
}
return itemoptions.AsEnumerable();