本文提供对Random的封装，简化并扩展了其功能

• 获取随机数，确保同时调用不会重复

   //new Random().Next(5); RandomTask.Next(5);

   

• 从一个列表中，随机获取其中某个值

              List<string> lsTest = new List<string>            {                "1","2","3","4","5"            };            string randomValue =http://www.mamicode.com/ RandomTask.PickOne(lsTest);            Console.WriteLine(randomValue);

   

• 从一个列表中，随机获取其中多个值

  List<string> someRandomValue = http://www.mamicode.com/RandomTask.PickAny(lsTest, 3);Console.WriteLine(string.Join(",", someRandomValue));

   

• 想按某个概率返回bool值，可以这么写

              bool is30Per = RandomTask.PickBoolByProp(0.3);            Console.WriteLine(is30Per);

   

• 最复杂的，一个list中有a，b两个数据，a按照70%概率返回而b按30%返回，就这样写

              Dictionary<string, double> lsTestAB = new Dictionary<string, double>            {                {"A",0.7 },                { "B",0.3}            };            string aOrb = RandomTask.PickOneByProb(lsTestAB);            Console.WriteLine(aOrb);

   

• 源码

      public static class RandomTask    {        private static readonly Random _random = new Random();        public static int Next()        {            lock (_random)            {                return _random.Next();            }        }        public static int Next(int max)        {            lock (_random)            {                return _random.Next(max);            }        }        public static int Next(int min, int max)        {            lock (_random)            {                return _random.Next(min, max);            }        }        /// <summary>        /// 按概率获取        /// </summary>        /// <param name="trueProp"></param>        /// <returns></returns>        public static bool PickBoolByProp(double trueProp = 1)        {            if (trueProp > 1)            {                trueProp = 1;            }            if (trueProp < 0)            {                trueProp = 0;            }            Dictionary<bool, double> wt = new Dictionary<bool, double>            {               { true , trueProp },               { false , 1 - trueProp }            };            return wt.PickOneByProb();        }        /// <summary>        /// 按指定概率获取随机结果        /// </summary>        /// <param name="sourceDic">a 0.8 b 0.1 c 0.1</param>        /// <returns>随机结果 [a,b,c]</returns>        public static T PickOneByProb<T>(this Dictionary<T, double> sourceDic)        {            if (sourceDic == null || !sourceDic.Any())            {                return default(T);            }            int seed = (int)(10 / (sourceDic.Values.Where(c => c > 0).Min()));            int maxValue = http://www.mamicode.com/sourceDic.Values.Aggregate(0, (current, d) => current + (int)(seed * d));            int rNum = Next(maxValue);            int tem = 0;            foreach (KeyValuePair<T, double> item in sourceDic)            {                tem += (int)(item.Value * seed);                if (tem > rNum)                {                    return item.Key;                }            }            return default(T);        }        /// <summary>        /// 随机从List中获取一项        /// </summary>        /// <typeparam name="T"></typeparam>        /// <param name="source"></param>        /// <returns></returns>        public static T PickOne<T>(this List<T> source)        {            if (source == null || !source.Any())            {                return default(T);            }            return source[Next(source.Count)];        }        /// <summary>        ///         /// </summary>        /// <typeparam name="T"></typeparam>        /// <param name="source"></param>        /// <param name="c"></param>        /// <returns></returns>        public static List<T> PickAny<T>(this List<T> source, int c)        {            if (source == null || !source.Any())            {                return default(List<T>);            }            if (source.Count <= c)            {                return source;            }            List<T> ls = new List<T>();            for (int i = 0; i < c; i++)            {                var t = source.PickOne();                if (!ls.Contains(t))                {                    ls.Add(t);                }            }            return ls;        }    }

   

• 大家试试吧，真的挺好用的

再来写一个随机数解决方案，对Random再来一次封装