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

namespace _1._11._14
{
    class Program
    {
        internal class Record
        {
            public int Id { get; set; }

            public string Name { get; set; }

            public int ParentID { get; set; }

            public Record(int a, string b, int? c)
            {
                Id = a;
                Name = b;
                if (c != null) ParentID = (int) c;
            }
        }

        private static void Main(string[] args)
        {
            var r11 = new Record(1, "Marc", null);
            var r12 = new Record(2, "Ivan", 1);
            var r13 = new Record(3, "Vasya", 2);

            var l = new List<Record> {r11, r12,r13};

            /*var l2 =
                from r in l                                 // query expression
                where r.ParentID == 1
                select new{Num = r.Id, FIO=r.Name};*/
            var l2 =
                l.Where(r => r.ParentID == 1)                 //LINQ
                .Select(r3 => new {Num = r3.Id, FIO = r3.Name});
            Console.WriteLine(l2.First());


            Console.ReadLine();
        }
    }
}