using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public class Comment {

        public bool hasSomething { get; set; } 

    }

    public class Registrations {

        public int Id { get; set; }

        public List<Comment> Comment { get; set; }

    }

    public static void Main()

    {

        Console.WriteLine("Hello World");

        List<Registrations> registrations = new List<Registrations>();

        registrations.Add(new Registrations { Id = 1, Comment = new List<Comment> {new Comment { hasSomething = false}}});

        registrations.Add(new Registrations { Id = 2, Comment = new List<Comment> {new Comment { hasSomething = false}}});

        registrations.Add(new Registrations { Id = 3, Comment = new List<Comment> {new Comment { hasSomething = true}}});

        registrations.Add(new Registrations { Id = 4, Comment = new List<Comment> {new Comment { hasSomething = false}}});

        registrations.Add(new Registrations { Id = 5, Comment = new List<Comment> {new Comment { hasSomething = true}}});

        registrations.Add(new Registrations { Id = 6, Comment = new List<Comment> {new Comment { hasSomething = false}}});

​

​

​

        registrations = registrations.OrderByDescending(x => x.Comment.Any(p => p.hasSomething == true)).ToList();

        foreach(var registration in registrations) {

            Console.WriteLine(registration.Id);

        }

    }

}