Sudoku using Microsoft Solver Foundation

using System;
using System.Collections.Generic;

namespace Sudoku
{
    public static class Utils
    {
        /* This method will return a list of unique random integers.
         * The minValue & maxValue will be used as the range.
         * count is the amount of random intergers that will be returned. */

        public static List<int> GetUniqueRandomNumbers(int minValue, int maxValue, int count)
        {
            List<int> randomIntegers = new List<int>();

            /* Check that the input parameters are valid */
            if (((maxValue - minValue) ) < count)
            {
                return null;
            }
            Random random = new Random();
            while (randomIntegers.Count < count)
            {
                int next = random.Next(minValue, maxValue);
                if (!randomIntegers.Contains(next))
                {
                    randomIntegers.Add(next);
                }
            }
            return randomIntegers;
        }

        public static int GetRandomNumber(int minValue, int maxValue)
        {
            return GetUniqueRandomNumbers(minValue, maxValue, 1)[0];
        }
    }
}