Question

I have this classes:

public class User
{
    [Key]
    public Guid UserId { get; set; }
    public string Address { get; set; }
    public double Latitude { get; set; }
    public double Longitude { get; set; }
    public string Units { get; set; }
    public int Distance { get; set; }

    public List<Sport> Sports { get; set; }
}

public class Sport
{
    [Key]
    public int SportId { get; set; }        
    public string Name { get; set; }        

    public List<User> Users { get; set; }
}

So, these classes, with the foreign keys many to many, generates in the database a table like that: SportUsers (SportId, UserId)

When a User, sign up, select from a listbox of Sports, the Sports in which he is interested. So in the Register action in the appropiate controller, I save the user like that:

db.Users.Add(user);
db.SaveChanges();

But, how can I save the list of sports in which the user is interested, in the autogenerated for the foreign key, SportUsers table ???

Answer 1

If your User has a collection of Sports, Entity Framework will figure out that that’s a M*N relationship and automatically fill the relationship in your database.