乱数生成の変更

    class NumberArray

    {

        private int[] number_;
        public NumberArray(int count)

        {

            number_ = new int[count];
            var rnd = new int[count];

            for (int i = 0; i < count; i++)

            {

                rnd[i] = i;

            }
            for (int i = 0, size = count; i < count; i++, size--)

            {

                var pos = new Random().Next(size);

                number_[i] = rnd[pos];
                for (int j = pos; j < size - 1; j++)

                {

                    rnd[j] = rnd[j + 1];

                }

            }

        }
        public int[] ToList()

        {

            return number_;

        }

    }

}

↓

    class NumberArray

    {

        private List number_;
        public NumberArray(int count)

        {

            var rnd = Enumerable.Range(0, count).ToList();
            number_ = new List(count);

            for (int i = 0; i < count; i++)

            {

                var pos = new Random().Next(rnd.Count);

                number_[i] = rnd[pos];

                rnd.RemoveAt(pos);

            }

        }
        public List ToList()

        {

            return number_;

        }

    }

ここに入ってる List を List に置換して、
呼び出し側を以下のように変更したい

    var rnd = new NumberArray(10).ToList();

↓

    var rnd = new NumberArray(10).ToList();