EFCore Generic Repository and UnitOfWork Design Pattern - entity-framework-core

Question

when im trying to create new data and save it, im getting error at the
public int Complete()
{
return _context.SaveChanges();
}
and error is saying me that:
The value of 'Agency.ID' is unknown when attempting to save changes. This is because the property is also part of a foreign key for which the principal entity in the relationship is not known. .
i have a Base class like that:
public class Base
{
protected Base()
{
CreatedDate = DateTime.Now;
IsDeleted = false;
ModifiedDate = null;
}
public int ID { get; set; }
public int? CreatedUserId { get; set; }
public int? ModifiedUserId { get; set; }
public string CreatedUserType { get; set; }
public string ModifiedUserType { get; set; }
public DateTime? CreatedDate { get; set; }
public DateTime? ModifiedDate { get; set; }
public bool? IsActive { get; set; }
public bool? IsDeleted { get; set; }
}
i have a Agency class like that :
public class Agency : Base
{
public Agency()
{
AgencyIsComplated = false;
}
[Required, StringLength(255)]
public string AgencyName { get; set; }
[Required, StringLength(255)]
public string AgencyPhoto { get; set; }
[Required, StringLength(255)]
public string AgencyEMail { get; set; }
[Required, StringLength(13)]
public string AgencyPhone { get; set; }
[StringLength(13)]
public string AgencyBPhone { get; set; }
[StringLength(255)]
public string AgencyInfo { get; set; }
[Required, StringLength(255)]
public string AgencyTitle { get; set; }
[Required, StringLength(255)]
public string AgencyLink { get; set; }
public int AgencyExportArea { get; set; } // Join table ile yapılacak,ayrı bir tabloda tutulacak
[Required, StringLength(255)]
public string AgencyInstagram { get; set; }
public string AgencyTwitter { get; set; }
public string AgencyFacebook { get; set; }
public string AgencyLinkedin { get; set; }
public string AgencyYoutube { get; set; }
public bool AgencyIsComplated { get; set; }
[ForeignKey("CompanyID")]
public Company Company { get; set; }
[ForeignKey("LogID")]
public Log Log { get; set; }
public virtual ICollection<AgencyCompany> AgencyCompanies { get; set; }
public virtual ICollection<User> Users { get; set; }
public virtual ICollection<Log> Logs { get; set; }
}
public class AgencyConfiguration : IEntityTypeConfiguration<Agency>
{
public void Configure(EntityTypeBuilder<Agency> builder)
{
builder.HasKey(agency => agency.ID);
builder.HasMany(a => a.Logs)
.WithOne(a => a.Agency)
.HasForeignKey(a=>a.ID)
.OnDelete(DeleteBehavior.Restrict);
builder.HasMany(us => us.Users)
.WithOne(us => us.Agency)
.HasForeignKey(au=>au.ID)
.OnDelete(DeleteBehavior.Restrict);
builder.HasMany(ac => ac.AgencyCompanies)
.WithOne(ac => ac.Agency)
.OnDelete(DeleteBehavior.Restrict);
}
}
and i have got a UnitOfWork like that:
public class UnitOfWork : IUnitOfWork
{
private TradeTurkDBContext _context;
public UnitOfWork(TradeTurkDBContext context)
{
_context = context;
RepositoryAgency = new RepositoryAgency(_context);
}
public IRepository Repository { get; private set; }
public IRepositoryAgency RepositoryAgency { get; private set; }
public int Complete()
{
return _context.SaveChanges();
}
public void Dispose()
{
_context.Dispose();
}
}
im inheriting that ID on my Base Model.
the problem is getting solved when im not defining ID in the base model but i allready set up my mapping on it.
so how can i solve that error without using AgencyID in the Agency model ?

Answer 1

The foreign key is in the details (or child) table. Therefore, e.g. a user, should have an AgencyId as foreign key.
builder.Entity<User>()
.HasOne(u => u.Agency)
.WithMany(a => a.Users)
.HasForeignKey(u => u.AgencyId)
.OnDelete(DeleteBehavior.Restrict);
This key automatically points to the primary key of the master (or parent) table.
User.ID is a primary key. User.AgencyId is a foreign key which (automatically) relates to the primary key Agency.ID.
E.g. see: Configure One-to-Many Relationships using Fluent API in Entity Framework Core