Error saving Entity framework

Question

I have a very basic problem, but I must be short of coffee to understand what is happening.

I have such an entity:

public class Client : BaseEntity<Client>
{
    [Required]
    public string CorporateName { get; set; }


    // Várias outras propriedades que eu tirei pra não ficar muita coisa


    public int UserID { get; set; }
    [ForeignKey("UserID")]
    public virtual User User { get; set; }

    public Client()
    {
        this.User = new User();
    }
}

So far, I don’t see any apparent problem. However, my Baseentity does Create this way (I created generic methods so that all my entities work the same way and I don’t have to replicate the same code several times):

public static void Add(params T[] items)
    {
        using (var context = new DBContext())
        {
            try
            {
                foreach (T item in items)
                    context.Entry(item).State = EntityState.Added;

                context.SaveChanges();
            }
            catch (DbEntityValidationException e)
            {
                foreach (var eve in e.EntityValidationErrors)
                {
                    Console.WriteLine("Entity of type \"{0}\" in state \"{1}\" has the following validation errors:",
                        eve.Entry.Entity.GetType().Name, eve.Entry.State);
                    foreach (var ve in eve.ValidationErrors)
                    {
                        Console.WriteLine("- Property: \"{0}\", Error: \"{1}\"",
                            ve.PropertyName, ve.ErrorMessage);
                    }
                }
                throw;
            }
        }
    }

When I try to add a Client, Add throws an error saying that the User property has the Name field that is required. However, I am setting the Userid and not the User (for a very noble reason: setting the User and doing the Add, it duplicated the User record).

How do I make Entityframework not try to add by my virtual property and add only by FK?

Answer 1

When I try to add a Client, Add throws an error saying that the User property has the Name field that is required. However, I am setting the Userid and not the User (for a very noble reason: setting the User and doing the Add, it duplicated the User record).

Yes, possibly you are not using the context to observe the User before.

How do I make Entity Framework not try to add by my virtual property and add only by FK?

There’s no such thing as "add to my virtual property". If the Entity Framework understands that its objects do not yet exist, it will insert as if they were new.

Its function Add can be considered an anti-standard. There is no verification of the associated entities before the addition. Right would be something like this:

var user = db.Users.FirstOrDefault(u => u.UserID == 1);
var client = new Client { User = user };
db.Clients.Add(client);
db.SaveChanges();

Selecting a user will make the context observe the record.

Now, if neither exists, the path is:

var user = new User { Name = "Fulano" };
var client = new Client { User = user };
db.Clients.Add(client);
db.SaveChanges();