core2

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication4
{
    class Program
    {
        static void Main(string[] args)
        {
            var somethings = new List<Something>
            {
                new Something(1,2,3),
                new Something(2,8,5),
                new Something(1,1,4),
                new Something(4,3,5),
                new Something(2,6,3),
                new Something(2,2,5),
                new Something(1,3,5),
                new Something(3,2,2),
                new Something(3,7,4),
            };

            var q = somethings.GroupBy(g => g.A).OrderBy(g => g.Key).SelectMany(g => g.OrderBy(x => x.B));

            foreach (var item in q)
            {
                Console.WriteLine("{0} {1} {2}", item.A, item.B, item.C);
            }

            Console.ReadLine();
        }
    }

    class Something
    {
        public int A { get; set; }
        public int B { get; set; }
        public int C { get; set; }

        public Something(int a, int b, int c)
        {
            A = a;
            B = b;
            C = c;
        }
    }
}