Problem mapping entities related to Fluent API

Question

I am starting with EF and I am having problems to map the relationship between my entities.

1. Entities

There are two entities in the project that I am using to practice the subject. They are:

• User
• Football team

A user has a single football team and this has n users.

1.1 User

public class Usuario
{
    public int UsuarioId { get; set; }
    public string UsuarioNome { get; set; }
    public string UsuarioEmail { get; set; }

    public int TimeFutebolId { get; set; }
    public TimeFutebol TimeFutebol { get; set; }
}

Note that I created the navigation property Football team for this entity. I also created the property Timefutebolid, because reading the EF documentation, I found a recommendation about creating a property that will be the key.

1.2 Football team

public class TimeFutebol
{
    public int TimeFutebolId { get; set; }
    public string TimeFutebolNome { get; set; }

    public ICollection<Usuario> Usuarios { get; set; }

    public TimeFutebol()
    {
        Usuarios = new List<Usuario>();
    }
}

Note that I also created the navigation property Users for this entity.

2. Database

2.1 Table User

Name of the table: User

I entered the user below in the table for test

2.2 Timesoccer Table

Table name: Timesoccer

Dbcontext

public class DataContext: DbContext
{
    public DataContext() : base("name=ConnString") { }

    public virtual DbSet<Usuario> Usuario { get; set; }
    public virtual DbSet<TimeFutebol> TimesFutebol { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Usuario>().ToTable("Usuario");
        modelBuilder.Entity<Usuario>().HasKey(x => x.Id);
        modelBuilder.Entity<Usuario>().Property(x => x.Id).HasColumnName("UsuarioId");
        modelBuilder.Entity<Usuario>().Property(x => x.Nome).HasColumnName("UsuarioNome");
        modelBuilder.Entity<Usuario>().Property(x => x.Email).HasColumnName("UsuarioEmail");
        modelBuilder.Entity<Usuario>().Property(x => x.TimeFutebolId).HasColumnName("TimeFutebolId");
        modelBuilder.Entity<Usuario>().HasRequired(x => x.TimeFutebol).WithMany(x => x.Usuarios).HasForeignKey(x => x.TimeFutebolId);

        modelBuilder.Entity<TimeFutebol>().ToTable("TimeFutebol");
        modelBuilder.Entity<TimeFutebol>().HasKey(x => x.Id);
        modelBuilder.Entity<TimeFutebol>().Property(x => x.Id).HasColumnName("TimeFutebolId");
        modelBuilder.Entity<TimeFutebol>().Property(x => x.Nome).HasColumnName("TimeFutebolNome");

        base.OnModelCreating(modelBuilder);
    }
}

Result after running the application

Note that the Timefootball property, from the first object on the list users, is empty. Already the User property, from the list of objects teams, has no object (Count = 0).

Answer 1

You did not put in question the code that performs the data query using the context and this makes it difficult to answer.

However, most likely using the Include as the code below you will be able to load the Timesoccer related to the User.

Example:

public ICollection<Usuario> GetAll()
{
    return context.Usuario.Include("TimeFutebol").ToList();
}

Answer 2

Change your Timefootball class to:

public class TimeFutebol
{
    public TimeFutebol()
    {
        Usuarios = new List<Usuario>();
    }

    public int TimeFutebolId { get; set; }
    public string TimeFutebolNome { get; set; }

    public ICollection<Usuario> Usuarios { get; set; }
}

Functional example: https://dotnetfiddle.net/9YnnEs

Answer 3

I only included the virtual in the navigation properties and worked. Example of one of the properties:

public virtual ICollection<Usuario> Usuarios { get; set; }