C# Model User, Friend Requests and Friends with Entity Framework Code First

Question

I have previously asked a question here on SO about a similar topic but have since taken a different approach. This is my model:

public class ApplicationUser         


        

Answer 1

@Mukesh thanks for your answer but I decided to take another approach since your solution did not get all rows in Friend were the user is either RequestedBy or RequestedTo. This is my solution:

public class ApplicationUser : IdentityUser
{
    public async Task GenerateUserIdentityAsync(UserManager manager, string authenticationType)
    {
        // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
        var userIdentity = await manager.CreateIdentityAsync(this, authenticationType);
        // Add custom user claims here
        return userIdentity;
    }

    public ApplicationUser()
    {
        SentFriendRequests = new List();
        ReceievedFriendRequests = new List();
    }

    [Required]
    public string Alias { get; set; }

    public string Name { get; set; }

    public byte[] ProfilePicture { get; set; }

    public virtual ICollection SentFriendRequests { get; set; }

    public virtual ICollection ReceievedFriendRequests { get; set; }

    [NotMapped]
    public virtual ICollection Friends {
        get
        {
            var friends = SentFriendRequests.Where(x => x.Approved).ToList();
            friends.AddRange(ReceievedFriendRequests.Where(x => x.Approved));
            return friends;
        } }
}

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

    modelBuilder.Conventions.Remove();
    modelBuilder.Conventions.Remove();

    modelBuilder.Entity()
        .HasRequired(a => a.RequestedBy)
        .WithMany(b => b.SentFriendRequests)
        .HasForeignKey(c => c.RequestedById);

    modelBuilder.Entity()
        .HasRequired(a => a.RequestedTo)
        .WithMany(b => b.ReceievedFriendRequests)
        .HasForeignKey(c => c.RequestedToId);
}

public class Friend
{
    [Key, Column(Order = 0)]
    public int RequestedById { get; set; } 
    [Key, Column(Order = 1)]
    public int RequestedToId { get; set; } 
    public virtual ApplicationUser RequestedBy { get; set; }
    public virtual ApplicationUser RequestedTo { get; set; }

    public DateTime? RequestTime { get; set; }

    public DateTime? BecameFriendsTime { get; set; }

    public FriendRequestFlag FriendRequestFlag { get; set; }

    [NotMapped]
    public bool Approved => FriendRequestFlag == FriendRequestFlag.Approved;

    public void AddFriendRequest(ApplicationUser user, ApplicationUser friendUser)
    {
        var friendRequest = new Friend()
        {
            RequestedBy = user,
            RequestedTo = friendUser,
            RequestTime = DateTime.Now,
            FriendRequestFlag = FriendRequestFlag.None
        };
        user.SentFriendRequests.Add(friendRequest);
    }
}

public enum FriendRequestFlag
{
    None,
    Approved,
    Rejected,
    Blocked,
    Spam
};