How do I select a random value from an enumeration

Question

Given an arbitrary enumeration in C   how do I select a random value    I did not find this very basic question on SO  I ll post my answer in a minute as reference for anyone  but please feel free to post your own answer

User · Answer

Here is a generic function for it  Keep the RNG creation outside the high frequency code   public static Random RNG   new Random     public static T RandomEnum lt T gt            Type type   typeof T       Array values   Enum GetValues type       lock RNG                object value  values GetValue RNG Next values Length            return  T Convert ChangeType value  type             Usage example    System Windows Forms Keys randomKey   RandomEnum lt System Windows Forms Keys gt

User · Answer

You can also cast a random value  using System   enum Test     Value1    Value2    Value3    class Program     public static void Main  string   args        var max   Enum GetValues typeof Test   Length      var value    Test new Random   Next 0  max - 1       Console WriteLine value          But you should use a better randomizer like the one in this library of mine

User · Answer

Adapted as a Random class extension   public static class RandomExtensions          public static T NextEnum lt T gt  this Random random                var values   Enum GetValues typeof T            return  T values GetValue random Next values Length              Example of usage   var random   new Random    var myEnumRandom   random NextEnum lt MyEnum gt

User · Answer

Array values   Enum GetValues typeof Bar    Random random   new Random    Bar randomBar    Bar values GetValue random Next values Length

User · Answer

Use Enum GetValues to retrieve an array of all values  Then select a random array item   static Random  R   new Random     static T RandomEnumValue lt T gt           var v   Enum GetValues  typeof  T        return  T  v GetValue   R Next v Length        Test   for  int i   0  i  lt  10  i          var value   RandomEnumValue lt System DayOfWeek gt          Console WriteLine  value ToString          -   Tuesday Saturday Wednesday Monday Friday Saturday Saturday Saturday Friday Wednesday

User · Answer

You could just do this      var rnd   new Random    return  MyEnum  rnd Next Enum GetNames typeof MyEnum   Length     No need to store arrays

User · Answer

Call Enum GetValues  this returns an array that represents all possible values for your enum  Pick a random item from this array  Cast that item back to the original enum type

User · Answer

Here s an alternative version as an Extension Method using LINQ     using System  using System Linq   public static class EnumExtensions       public static Enum GetRandomEnumValue this Type t                return Enum GetValues t              get values from Type provided              OfType lt Enum gt                     casts to Enum              OrderBy e   gt  Guid NewGuid       mess with order of results              FirstOrDefault                  take first item in result          public static class Program       public enum SomeEnum               One   1          Two   2          Three   3          Four   4            public static void Main                 for int i 0  i  lt  10  i                          Console WriteLine typeof SomeEnum  GetRandomEnumValue                                       Two    One    Four    Four    Four    Three    Two    Four    One    Three

User · Answer

Personally  I m a fan of extension methods  so I would use something like this  while not really an extension  it looks similar    public enum Options       Zero      One      Two      Three      Four      Five    public static class RandomEnum       private static Random  Random   new Random Environment TickCount        public static T Of lt T gt              if   typeof T  IsEnum              throw new InvalidOperationException  Must use Enum type             Array enumValues   Enum GetValues typeof T            return  T enumValues GetValue  Random Next enumValues Length              TestClass  public class RandomTests        TestMethod      public void TestMethod1             Options option          for  int i   0  i  lt  10    i                option   RandomEnum Of lt Options gt                 Console WriteLine option

[c#] How do I select a random value from an enumeration?

Examples related to c#

Examples related to random

Examples related to enums