using System;

using System.Linq;

using System.Collections.Generic;

​

public class Load

{

    public string Name;

    public int Id;

    public int? PredecessorId;

}

public class Program

{

    public static void Main()

    {

        var loads = new List<Load>();

        var sortedloads = new List<Load>();

        var loadA1 = new Load() {Id = 1, PredecessorId = null , Name ="loadA1"};

        var loadA2 = new Load() {Id = 2, PredecessorId = loadA1.Id, Name ="loadA2"};

        var loadA3 = new Load() {Id = 3, PredecessorId = loadA2.Id, Name ="loadA3"};

        var loadB1 = new Load() {Id = 4, PredecessorId = null, Name ="loadB1"};

        var loadB2 = new Load() {Id = 5, PredecessorId = loadB1.Id, Name ="loadB2"};

        var loadB3 = new Load() {Id = 6, PredecessorId = loadB2.Id, Name ="loadB3"};

        var loadB4 = new Load() {Id = 7, PredecessorId = loadB3.Id, Name ="loadB4"};

        loads.Add(loadB4);

        loads.Add(loadB2);

        loads.Add(loadA1);

        loads.Add(loadA3);

        loads.Add(loadB3);

        loads.Add(loadA2);

        loads.Add(loadB1);

        loads = loads.OrderBy(q => !loads.Any(load => load.Id == q.PredecessorId)).ThenBy(q => q.PredecessorId == null).ToList();

​

        int count = 0;

        while(loads.Count > 0)

        {

            Console.WriteLine("Finished" + count++);

            sortedloads.AddRange(loads.Where(q => !loads.Any(p => q.PredecessorId == p.Id)));

            loads.RemoveAll(load => sortedloads.Contains(load));

        }

        foreach(var load in sortedloads)

        {

            Console.WriteLine("Name:" + load.Name + ", ID: " + load.Id + ", Predecessor ID: " + load.PredecessorId);

        }

    }

}