Entity Framework - How to configure the User Roles Many to Many Relationship

Question

Below is the definition of the User entity, there is a navigation property Roles

    public class User
    {
        public User()
        {
            Roles = new List<Role>();
        }

        public string Id { get; set; }

        public string Username { get; set; }

        public virtual ICollection<Role> Roles { get; set; }

Below is definition of the Role entity

public class Role
{
    public string Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }

What i want is to define the many to many relationship and generate a relationship table UserRole which use UserId as the left key and RoleId as the right key, so how to write the configuration code?

Answer 1

User:

public class User
{
    public User()
    {
        Roles = new List<Role>();
    }

    public string Id { get; set; }
    public string Username { get; set; }
    public virtual ICollection<UserRole> Roles { get; set; }
}

Role:

public class Role
{
    public string Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

UserRole:

public class UserRole
{
    public string Id { get; set; }
    public string UserId { get; set; }
    public string RoleId{ get; set; }

    public virtual User User { get; set; }
    public virtual Role Role { get; set; }
}

Override the OnModelCreating method in your dbcontext:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    modelBuilder.Entity<User>()
        .HasMany(c => c.Roles )
        .WithMany()                 
        .Map(x =>
        {
            x.MapLeftKey("UserId");
            x.MapRightKey("RoleId");
            x.ToTable("UserRoles");
        });
}