c# Random Class usage

Random Usage

sometimes, we hope to generate some random infor to manipulate our data structor. we can use random class to achieve this goal.

the refer link in MSDN,Random

example source

using System;
using System.Text;
using System.Windows.Media;

namespace MVVM_Template_Project.Auxiliary.Helpers
{
    /// <summary>
    /// This class should provide you with plenty of random method to get random things.
    /// Benefit: no need to create a `Random rand = new Randow();` everywhere in your code.
    /// </summary>
    public static class Random_Helper
    {
        private static readonly Random RandomSeed = new Random();

        /// <summary>
        /// Generates a random string with the given length
        /// </summary>
        /// <param name="size">Size of the string</param>
        /// <param name="lowerCase">If true, generate lowercase string</param>
        /// <returns>Random string</returns>
        public static string RandomString(int size, bool lowerCase)
        {
            // StringBuilder is faster than using strings (+=)
            var randStr = new StringBuilder(size);

            // Ascii start position (65 = A / 97 = a)
            var start = (lowerCase) ? 97 : 65;

            // Add random chars
            for (var i = 0; i < size; i++)
                randStr.Append((char) (26*RandomSeed.NextDouble() + start));

            return randStr.ToString();
        }

        /// <summary>
        /// Number between min (inclusive) and max (exclusive)
        /// </summary>
        /// <param name="min">Inclusive</param>
        /// <param name="max">Exclusive</param>
        /// <returns></returns>
        public static int RandomInt(int min, int max)
        {
            return RandomSeed.Next(min, max);
        }

        /// <summary>
        /// Double between 0 (inclusive) and 1 (exclusive)
        /// </summary>
        public static double RandomDouble()
        {
            return RandomSeed.NextDouble();
        }

        /// <summary>
        /// Return a random number between min (inc) and max (exc), with 'digits'
        /// numbers after the decimal point.
        /// </summary>
        /// <param name="min">Lowest number (inclusive)</param>
        /// <param name="max">Highest number (exclusive)</param>
        /// <param name="digits">Precision after decimal point</param>
        public static double RandomNumber(int min, int max, int digits)
        {
            var range 		= max-min;
            var str_format 	= "{0:F"+digits+"}";
            // To avoid having to get an int and then add a random double ...
            var rand_dou 	= Double.Parse(string.Format(str_format, min + range * RandomSeed.NextDouble()));

            // If for some random reason the rounding of the double is equal to max, we just call
            // the method again and return the value.
            // This can *theoretically* get into an infinite loop if it happens every time, but
            // this scenario is highly unlikely :0
            return (rand_dou<max) ? rand_dou : RandomNumber(min,max, digits) ; 

            /*
            * Another option will be:
            * return Math.Round(RandomSeed.Next(min, max - 1) + RandomSeed.NextDouble(), digits);
            */
        }

        /// <summary>
        /// Random true/false.
        /// </summary>
        public static bool RandomBool()
        {
            return (RandomSeed.NextDouble() > 0.5);
        }

        /// <summary>
        /// Random phone nmuber. Starts with 1234 and has extra 6 random digts.
        /// </summary>
        public static string RandomPhone()
        {
            string mold = "1234-{0}-{1}";
            return string.Format(mold, RandomInt(0, 1000).ToString().PadLeft(3, '0'), RandomInt(0, 1000).ToString().PadLeft(3, '0'));
        }

        /// <summary>
        /// Will return a random date between 1/1/1900 and Now.
        /// </summary>
        public static DateTime RandomDate()
        {
            return RandomDate(new DateTime(1900, 1, 1), DateTime.Now);
        }

        /// <summary>
        /// Will return a random date between given dates.
        /// </summary>
        /// <param name="from">lower bound date</param>
        /// <param name="to">higher bound date</param>
        /// <returns></returns>
        public static DateTime RandomDate(DateTime from, DateTime to)
        {
            var range = new TimeSpan(to.Ticks - from.Ticks);
            return from + new TimeSpan((long) (range.Ticks*RandomSeed.NextDouble()));
        }

        /// <summary>
        /// Random color (RGB)
        /// </summary>
        public static Color RandomColor()
        {
            return Color.FromRgb((byte) RandomSeed.Next(255), (byte) RandomSeed.Next(255), (byte) RandomSeed.Next(255));
        }

        /// <summary>
        /// Random weather. Note that valid values are 0-5 (inclusive), and so the
        /// default might happen.
        /// </summary>
        /// <returns></returns>
        public static string RandomWeather()
        {
            int rand = RandomInt(0, 6);
            string weather;
            switch (rand)
            {
                case 0:
                    weather = "Gloomy day";
                    break;
                case 1:
                    weather = "Rainy day";
                    break;
                case 2:
                    weather = "Foggy day";
                    break;
                case 3:
                    weather = "Sunny day";
                    break;
                case 4:
                    weather = "Rainy with a chance of meatballs";
                    break;
                default:
                    weather = "I'm stuck in my cubicle coding. No weather for you! Come back, 1 YEAR!";
                    break;
            }
            return weather;
        }

        #region Random names

        private static readonly string[] ListOfMaleFirstNames =
        {
            "Verna", "Almeta",
            "Melvina", "Digna", "Dortha", "Ione", "Sonya", "Shiela", "Shonna",
            "Tania", "Susanne", "Ellie", "Felice", "Caitlyn", "Bethel", "Kamilah",
            "Camila", "Stefanie", "Daysi", "Brittaney", "Lavonda", "Janice",
            "Tiny", "Peg", "Kaila", "Janay", "Inga", "Melissa", "Delila", "Patience",
            "Delma", "Ressie", "Nenita", "Casimira", "Theda", "Ethel", "Christinia",
            "Nyla", "Letha", "Lea", "Cindy", "Nancy", "Jazmine", "Vanita", "Larhonda",
            "Tai", "Charise", "Latoria", "Shanti", "Kyla"
        };
        private static readonly int MaleFirstNamesCount = ListOfMaleFirstNames.Length;

        private static readonly string[] ListOfFemaleFirstNames =
        {
            "Verna", "Almeta",
            "Melvina", "Digna", "Dortha", "Ione", "Sonya", "Shiela", "Shonna",
            "Tania", "Susanne", "Ellie", "Felice", "Caitlyn", "Bethel", "Kamilah",
            "Camila", "Stefanie", "Daysi", "Brittaney", "Lavonda", "Janice",
            "Tiny", "Peg", "Kaila", "Janay", "Inga", "Melissa", "Delila", "Patience",
            "Delma", "Ressie", "Nenita", "Casimira", "Theda", "Ethel", "Christinia",
            "Nyla", "Letha", "Lea", "Cindy", "Nancy", "Jazmine", "Vanita", "Larhonda",
            "Tai", "Charise", "Latoria", "Shanti", "Kyla"
        };
        private static readonly int FemaleFirstNamesCount = ListOfFemaleFirstNames.Length;

        private static readonly string[] ListOfLastNames =
        {
            "Smith", "Jones", "Williams", "Brown", "Wilson", "Taylor", "Morton", "White",
            "Martin", "Anderson", "Thompson", "Nguyen", "Thomas", "Walker", "Harris",
            "Lee", "Ryan", "Robinson", "Kelly", "King", "González", "Rodríguez",
            "Hernández", "Pérez", "García", "Martín", "Santana", "Díaz", "Suárez",
            "Sánchez", "Smith", "Brown", "Lee", "Wilson", "Martin", "Patel", "Taylor",
            "Wong", "Campbell", "Williams", "Kim", "Lee", "Park", "Choi", "Jeong",
            "Kang", "Cho", "Yoon", "Jang", "Lim"
        };
        private static readonly int LastNamesCount = ListOfLastNames.Length;

        #endregion
        /// <summary>
        /// Return a random name. Might be male/female and with a diverse last name range.
        /// </summary>
        /// <param name="aMale">If true will return male name</param>
        /// <param name="aFemale">If true will return female name</param>
        /// <returns>If both param are true or null, random name. Otherwise, male or female
        /// name depending on the param that is true</returns>
        public static string RandomName(bool? aMale=null, bool? aFemale=null)
        {
            string first;
            // Not specified, select at random
            if ((aMale == null && aFemale == null) ||
                (aMale == true && aFemale == true))
            {
                var gender = RandomBool();
                first = (gender) ? ListOfMaleFirstNames[RandomInt(0, MaleFirstNamesCount)]
                                : ListOfFemaleFirstNames[RandomInt(0, FemaleFirstNamesCount)];
            }
            else if (aMale == true)
                first = ListOfMaleFirstNames[RandomInt(0, MaleFirstNamesCount)];
            else
                first = ListOfFemaleFirstNames[RandomInt(0, FemaleFirstNamesCount)];

            string last = ListOfLastNames[RandomInt(0, LastNamesCount)];
            return string.Format("{0} {1}", first, last);
        }

    }
}

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