using static System.Console;

using System.Collections.Generic;

​

public static class Sorteio {

    public static void Main() {

        var lista = new List<string>() { "Alaor", "Joseval", "Salustiano", "Gomide", "Castro" };

        lista.Shuffle();

        foreach (var valor in lista) {

            WriteLine(valor);

        }

        WriteLine("//////////");

        string[] array = { "Alaor", "Joseval", "Salustiano", "Gomide", "Castro" };

        array.Shuffle(2);

        foreach (var valor in array) {

            WriteLine(valor);

        }

        WriteLine("//////////");

        int[] array2 = { 1, 2, 3, 4, 5 };

        array2.Shuffle(1,4);

        foreach (var valor in array2) {

            WriteLine(valor);

        }

    }

}

​

namespace System.Collections.Generic {

    public static class IListExt {

        static Random r = new Random(DateTime.Now.Millisecond);

​

        public static void Shuffle<T>(this IList<T> list, int lowerItem, int upperItem) {

            upperItem = upperItem > list.Count ? list.Count : upperItem;

            lowerItem = lowerItem < 0 ? 0 : lowerItem;

            for (int i = lowerItem; i < upperItem; i++) {

                int j = r.Next(i, upperItem);

                T tmp = list[j];

                list[j] = list[i];

                list[i] = tmp;

            }

        }

​

        public static void Shuffle<T>(this IList<T> list, int upperItem) {

            list.Shuffle(0, upperItem);

        }

​

        public static void Shuffle<T>(this IList<T> list) {

            list.Shuffle(0, list.Count);

        }

    }

}