LivreLand/Model/Contact.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Model
{
    public class Contact : IEquatable<Contact>
    {
        public string Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }

        public bool Equals(Contact? other)
            => Id == other.Id;

        public override bool Equals(object? obj)
        {
            if (ReferenceEquals(obj, null)) return false;
            if (ReferenceEquals(this, obj)) return true;
            if (GetType() != obj.GetType()) return false;
            return Equals(obj as Contact);
        }

        public override int GetHashCode()
            => Id.GetHashCode();
    }
}