C# 下快速生成不重复的随机数

    /// 

    /// 随机数帮助类
    /// 
    public class RandomHelper
    {
        #region 单例构造函数

        private RandomHelper()
        {
        }

        public static RandomHelper Instance
        {
            get
            {
                return Nested.instance;
            }
        }

        private class Nested
        {
            // Explicit static constructor to tell C# compiler
            // not to mark type as beforefieldinit
            static Nested()
            {
            }

            internal static readonly RandomHelper instance = new RandomHelper();
        }

        #endregion

        /// 

        /// 随机生成一组有上下界的数
        /// 
        /// 上届
        /// 下届
        /// 数量
        /// 
        public List RandomNumbers(int minValue, int maxValue, int count)
        {
            if (Equals(minValue, maxValue)) return null;
            if (count > Math.Abs(maxValue - minValue)) return null;

            //生成一个包含所有可取数的链表
            var num = minValue;
            var numList = new List { num };
            while (num++ < maxValue)
            {
                numList.Add(num);
            }

            //洗牌
            for (int index = 0; index < numList.Count; index++)
            {
                var flag = Random(minValue, maxValue);

                var temp = numList[index];
                numList[index] = numList[Math.Abs(flag - index) % numList.Count];
                numList[Math.Abs(flag - index) % numList.Count] = temp;
            }

            //移除多余项
            numList.RemoveRange(count, numList.Count - count);

            return numList;
        }

        /// 

        /// 随机生成一个数
        /// 
        /// 
        public int Random()
        {
            return Math.Abs(Guid.NewGuid().GetHashCode());
        }

        /// 

        /// 随机生成一个有上界的数 random <= maxValue
        /// 
        /// 上界
        /// 
        public int Random(int maxValue)
        {
            return Math.Abs(Random() % (maxValue + 1));
        }

        /// 

        /// 随机生成一个有区间的数   minValue <= random <= maxValue
        /// 
        /// 下界
        /// 上界
        /// 
        public int Random(int minValue, int maxValue)
        {
            var value = Random(maxValue);

            return value >= minValue ? value : (Math.Abs(minValue - value) % (maxValue - minValue) + minValue);
        }
    }

    class Program
    {
        static Dictionary dict = new Dictionary
            {
                { 0,"0000"},
                { 1,"000"},
                { 2,"00"},
                { 3,"0"},
                { 4,string.Empty}
            };

        static void Main(string[] args)
        {
            var arry = new int[10];
            Console.WriteLine("随机生成1000000个数。");
            Console.WriteLine("开始生成。");
            var watch = new Stopwatch();
            watch.Start();  //开始监视代码运行时间
            for (int i = 0; i < 1000000; i++)
                arry[RandomHelper.Instance.Random(0, 9)]++;
            watch.Stop();  //停止监视
            var timespan = watch.Elapsed;
            Console.WriteLine();
            Console.WriteLine("生成结束。");
            Console.WriteLine("执行时间：{0}(毫秒)", timespan.TotalMilliseconds);

            int index = 0;
            arry.ToList().ForEach(p => Console.WriteLine(string.Format("生成数字“{0}”的次数：{1}", index++, p.ToString())));


            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine();


            Console.WriteLine("随机生成1000个非重复的数。");
            Console.WriteLine("开始生成。");
            var watch2 = new Stopwatch();
            watch2.Start();  //开始监视代码运行时间
            var result = RandomHelper.Instance.RandomNumbers(0, 1000, 1000);
            watch2.Stop();  //停止监视
            var timespan2 = watch2.Elapsed;
            Console.WriteLine();
            Console.WriteLine("生成结束。");
            Console.WriteLine("执行时间：{0}(毫秒)", timespan2.TotalMilliseconds);
            Console.WriteLine("生成结果：");
            index = 0;
            result.ForEach(p =>
            {
                if (!Equals(index, 0) && Equals(index % 25, 0))
                    Console.WriteLine();
                Console.Write(string.Format("{0} ", string.Format("{0}{1}", dict[p.ToString().Length], p)));
                index++;
            });
            Console.ReadKey();
        }
    }