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();
}
question from:
https://stackoverflow.com/questions/65874906/the-expression-y-cases-is-invalid-inside-an-include-operation