How to enumerate an enum

Question

How can you enumerate an enum in C    E g  the following code does not compile   public enum Suit       Spades      Hearts      Clubs      Diamonds    public void EnumerateAllSuitsDemoMethod         foreach  Suit suit in Suit                DoSomething suit             And it gives the following compile-time error       Suit  is a  type  but is used like a  variable    It fails on the Suit keyword  the second one

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foreach  Suit suit in  Suit    Enum GetValues typeof Suit          Note  The cast to  Suit    is not strictly necessary  but it does make the code 0 5 ns faster

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Also you can bind to the public static members of the enum directly by using reflection   typeof Suit  GetMembers BindingFlags Public   BindingFlags Static       ToList   ForEach x   gt  DoSomething x Name

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For getting a list of int from an enum  use the following  It works  List lt int gt  listEnumValues   new List lt int gt     YourEnumType   myEnumMembers    YourEnumType   Enum GetValues typeof YourEnumType    foreach   YourEnumType enumMember in myEnumMembers        listEnumValues Add enumMember GetHashCode

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You won t get Enum GetValues   in Silverlight   Original Blog Post by Einar Ingebrigtsen   public class EnumHelper       public static T   GetValues lt T gt                  Type enumType   typeof T            if   enumType IsEnum                        throw new ArgumentException  Type      enumType Name      is not an enum                       List lt T gt  values   new List lt T gt              var fields   from field in enumType GetFields                        where field IsLiteral                      select field           foreach  FieldInfo field in fields                        object value   field GetValue enumType               values Add  T value                      return values ToArray               public static object   GetValues Type enumType                if   enumType IsEnum                        throw new ArgumentException  Type      enumType Name      is not an enum                       List lt object gt  values   new List lt object gt              var fields   from field in enumType GetFields                        where field IsLiteral                      select field           foreach  FieldInfo field in fields                        object value   field GetValue enumType               values Add value                      return values ToArray

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Three ways    Enum GetValues type     Since  NET 1 1  not in Silverlight or  NET Compact Framework type GetEnumValues      Only on  NET 4 and above type GetFields   Where x   gt  x IsLiteral  Select x   gt  x GetValue null      Works everywhere   I am not sure why GetEnumValues was introduced on type instances  It isn t very readable at all for me     Having a helper class like Enum lt T gt  is what is most readable and memorable for me   public static class Enum lt T gt  where T   struct  IComparable  IFormattable  IConvertible       public static IEnumerable lt T gt  GetValues                 return  T   Enum GetValues typeof T               public static IEnumerable lt string gt  GetNames                 return Enum GetNames typeof T              Now you call   Enum lt Suit gt  GetValues        Or Enum GetValues typeof Suit       Pretty consistent style   One can also use some sort of caching if performance matters  but I don t expect this to be an issue at all   public static class Enum lt T gt  where T   struct  IComparable  IFormattable  IConvertible          Lazily loaded     static T   values      static string   names       public static IEnumerable lt T gt  GetValues                 return values     values    T   Enum GetValues typeof T                public static IEnumerable lt string gt  GetNames                 return names     names   Enum GetNames typeof T

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It looks to me like you really want to print out the names of each enum  rather than the values  In which case Enum GetNames   seems to be the right approach   public enum Suits       Spades      Hearts      Clubs      Diamonds      NumSuits    public void PrintAllSuits         foreach  string name in Enum GetNames typeof Suits                  System Console WriteLine name             By the way  incrementing the value is not a good way to enumerate the values of an enum  You should do this instead   I would use Enum GetValues typeof Suit   instead   public enum Suits       Spades      Hearts      Clubs      Diamonds      NumSuits    public void PrintAllSuits         foreach  var suit in Enum GetValues typeof Suits                  System Console WriteLine suit ToString

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I think you can use  Enum GetNames Suit

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A simple and generic way to convert an enum to something you can interact   public static Dictionary lt int  string gt  ToList lt T gt    where T   struct      return   IEnumerable lt T gt  Enum         GetValues typeof T            ToDictionary             item   gt  Convert ToInt32 item              item   gt  item ToString         And then   var enums   EnumHelper ToList lt MyEnum gt

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Use Cast lt T gt    var suits   Enum GetValues typeof Suit   Cast lt Suit gt       There you go  IEnumerable lt Suit gt

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enum types are called  enumeration types  not because they are containers that  enumerate  values  which they aren t   but because they are defined by enumerating the possible values for a variable of that type     Actually  that s a bit more complicated than that - enum types are considered to have an  underlying  integer type  which means each enum value corresponds to an integer value  this is typically implicit  but can be manually specified   C  was designed in a way so that you could stuff any integer of that type into the enum variable  even if it isn t a  named  value    The System Enum GetNames method can be used to retrieve an array of strings which are the names of the enum values  as the name suggests   EDIT  Should have suggested the System Enum GetValues method instead  Oops

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I know it is a bit messy  but if you are fan of one-liners  here is one     Suit   Enum GetValues typeof Suit    ToList   ForEach i   gt  DoSomething i

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There are two ways to iterate an Enum   1  var values    Enum GetValues typeof myenum   2  var values    Enum GetNames typeof myenum     The first will give you values in form on an array of   object  s  and the second will give you values in form of an array of   String  s   Use it in a foreach loop as below   foreach var value in values           Do operations here

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foreach  Suit suit in Enum GetValues typeof Suit              I ve heard vague rumours that this is   terifically slow  Anyone know      Orion   Edwards Oct 15  08 at 1 31 7      I think caching the array would speed it up considerably   It looks like you re getting a new array  through reflection  every time   Rather   Array enums   Enum GetValues typeof Suit    foreach  Suit suitEnum in enums         DoSomething suitEnum       That s at least a little faster  ja

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What if you know the type will be an enum  but you don t know what the exact type is at compile time   public class EnumHelper       public static IEnumerable lt T gt  GetValues lt T gt                  return Enum GetValues typeof T   Cast lt T gt                public static IEnumerable getListOfEnum Type type                MethodInfo getValuesMethod   typeof EnumHelper  GetMethod  GetValues   MakeGenericMethod type           return  IEnumerable getValuesMethod Invoke null  null             The method getListOfEnum uses reflection to take any enum type and returns an IEnumerable of all enum values   Usage   Type myType   someEnumValue GetType     IEnumerable resultEnumerable   getListOfEnum myType    foreach  var item in resultEnumerable        Console WriteLine String Format  Item   0  Value   1   item ToString    int item

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Just by combining the top answers  I threw together a very simple extension   public static class EnumExtensions            lt summary gt          Gets all items for an enum value           lt  summary gt           lt typeparam name  T  gt  lt  typeparam gt           lt param name  value  gt The value  lt  param gt           lt returns gt  lt  returns gt      public static IEnumerable lt T gt  GetAllItems lt T gt  this T value  where T   Enum               return  T   Enum GetValues typeof  T              It is clean  simple  and  by  Jeppe-Stig-Nielsen s comment  fast

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public void PrintAllSuits         foreach string suit in Enum GetNames typeof Suits                  Console WriteLine suit

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When you have a bit enum like this enum DemoFlags       DemoFlag   1      OtherFlag   2      TestFlag   4      LastFlag   8     With this assignement DemoFlags demoFlags   DemoFlags DemoFlag   DemoFlags TestFlag   and need a result like this  quot DemoFlag   TestFlag quot   this method helps  public static string ConvertToEnumString lt T gt  T enumToConvert  string separator    quot     quot   where T   Enum       StringBuilder convertedEnums   new StringBuilder         foreach  T enumValue in Enum GetValues typeof T                  if  enumToConvert HasFlag enumValue   convertedEnums Append   quot   enumValue   separator  quot               if  convertedEnums Length  gt  0  convertedEnums Length -  separator Length       return convertedEnums ToString

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I made some extensions for easy enum usage  Maybe someone can use it     public static class EnumExtensions            lt summary gt          Gets all items for an enum value           lt  summary gt           lt typeparam name  T  gt  lt  typeparam gt           lt param name  value  gt The value  lt  param gt           lt returns gt  lt  returns gt      public static IEnumerable lt T gt  GetAllItems lt T gt  this Enum value                foreach  object item in Enum GetValues typeof T                          yield return  T item                            lt summary gt          Gets all items for an enum type           lt  summary gt           lt typeparam name  T  gt  lt  typeparam gt           lt param name  value  gt The value  lt  param gt           lt returns gt  lt  returns gt      public static IEnumerable lt T gt  GetAllItems lt T gt    where T   struct               foreach  object item in Enum GetValues typeof T                          yield return  T item                            lt summary gt          Gets all combined items from an enum value           lt  summary gt           lt typeparam name  T  gt  lt  typeparam gt           lt param name  value  gt The value  lt  param gt           lt returns gt  lt  returns gt           lt example gt          Displays ValueA and ValueB           lt code gt          EnumExample dummy   EnumExample Combi          foreach  var item in dummy GetAllSelectedItems lt EnumExample gt                          Console WriteLine item                      lt  code gt           lt  example gt      public static IEnumerable lt T gt  GetAllSelectedItems lt T gt  this Enum value                int valueAsInt   Convert ToInt32 value  CultureInfo InvariantCulture            foreach  object item in Enum GetValues typeof T                          int itemAsInt   Convert ToInt32 item  CultureInfo InvariantCulture                if  itemAsInt     valueAsInt  amp  itemAsInt                                 yield return  T item                                          lt summary gt          Determines whether the enum value contains a specific value           lt  summary gt           lt param name  value  gt The value  lt  param gt           lt param name  request  gt The request  lt  param gt           lt returns gt               lt c gt true lt  c gt  if value contains the specified value  otherwise   lt c gt false lt  c gt            lt  returns gt           lt example gt           lt code gt          EnumExample dummy   EnumExample Combi          if  dummy Contains lt EnumExample gt  EnumExample ValueA                         Console WriteLine  dummy contains EnumExample ValueA                       lt  code gt           lt  example gt      public static bool Contains lt T gt  this Enum value  T request                int valueAsInt   Convert ToInt32 value  CultureInfo InvariantCulture           int requestAsInt   Convert ToInt32 request  CultureInfo InvariantCulture            if  requestAsInt     valueAsInt  amp  requestAsInt                         return true                     return false            The enum itself must be decorated with the FlagsAttribute    Flags  public enum EnumExample       ValueA   1      ValueB   2      ValueC   4      ValueD   8      Combi   ValueA   ValueB

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My solution works in  NET Compact Framework  3 5  and supports type checking at compile time   public static List lt T gt  GetEnumValues lt T gt    where T   new         T valueType   new T        return typeof T  GetFields            Select fieldInfo   gt   T fieldInfo GetValue valueType            Distinct            ToList       public static List lt String gt  GetEnumNames lt T gt          return typeof  T  GetFields            Select info   gt  info Name           Distinct            ToList         If anyone knows how to get rid of the T valueType   new T    I d be happy to see a solution    A call would look like this   List lt MyEnum gt  result   Utils GetEnumValues lt MyEnum gt

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If you need speed and type checking at build and run time  this helper method is better than using LINQ to cast each element   public static T   GetEnumValues lt T gt    where T   struct  IComparable  IFormattable  IConvertible       if  typeof T  BaseType    typeof Enum                 throw new ArgumentException string Format   0  is not of type System Enum   typeof T               return Enum GetValues typeof T   as T        And you can use it like below   static readonly YourEnum    values   GetEnumValues lt YourEnum gt       Of course you can return IEnumerable lt T gt   but that buys you nothing here

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This question appears in Chapter 10 of  C  Step by Step 2013   The author uses a double for-loop to iterate through a pair of Enumerators  to create a full deck of cards    class Pack       public const int NumSuits   4      public const int CardsPerSuit   13      private PlayingCard    cardPack       public Pack                 this cardPack   new PlayingCard NumSuits  CardsPerSuit           for  Suit suit   Suit Clubs  suit  lt   Suit Spades  suit                          for  Value value   Value Two  value  lt   Value Ace  value                                  cardPack  int suit   int value    new PlayingCard suit  value                                     In this case  Suit and Value are both enumerations   enum Suit   Clubs  Diamonds  Hearts  Spades   enum Value   Two  Three  Four  Five  Six  Seven  Eight  Nine  Ten  Jack  Queen  King  Ace    and PlayingCard is a card object with a defined Suit and Value   class PlayingCard       private readonly Suit suit      private readonly Value value       public PlayingCard Suit s  Value v                this suit   s          this value   v

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New  NET 5 solution   NET 5 has introduced a a generic version for the GetValues method  Suit   suitValues   Enum GetValues lt Suit gt      Usage in a foreach loop  foreach  Suit suit in Enum GetValues lt Suit gt           which is now by far the most convenient solution

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LINQ Generic Way       public static Dictionary lt int  string gt  ToList lt T gt    where T   struct   gt            IEnumerable lt T gt  Enum GetValues typeof T    ToDictionary value   gt  Convert ToInt32 value   value   gt  value ToString       Usage           var enums   ToList lt Enum gt

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Add method public static IEnumerable lt T gt  GetValues lt T gt    to your class  like   public static IEnumerable lt T gt  GetValues lt T gt          return Enum GetValues typeof T   Cast lt T gt         Call and pass your enum  Now you can iterate through it using foreach    public static void EnumerateAllSuitsDemoMethod              Custom method      var foos   GetValues lt Suit gt          foreach  var foo in foos                     Do something

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I think its help you try it  public class Program        public static List lt T gt  GetEnamList lt T gt                  var enums   Enum GetValues typeof T   Cast lt T gt    Select v   gt  v  ToList            return enums            private void LoadEnumList                 List lt DayofWeek gt  dayofweeks   GetEnamList lt DayofWeek gt              foreach  var item in dayofweeks                        dayofweeks Add item                          public enum DayofWeek               Monday          Tuesday          Wensday          Thursday          Friday          Sturday          Sunday

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If you have   enum Suit      Spades     Hearts     Clubs     Diamonds     This   foreach  var e in Enum GetValues typeof Suit          Console WriteLine e ToString              int e       Will output   Spades   0 Hearts   1 Clubs   2 Diamonds   3

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Some versions of the  NET framework do not support Enum GetValues  Here s a good workaround from Ideas 2 0  Enum GetValues in Compact Framework   public Enum   GetValues Enum enumeration        FieldInfo   fields   enumeration GetType   GetFields BindingFlags Static   BindingFlags Public       Enum   enumerations   new Enum fields Length        for  var i   0  i  lt  fields Length  i            enumerations i     Enum  fields i  GetValue enumeration        return enumerations      As with any code that involves reflection  you should take steps to ensure it runs only once and results are cached

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foreach  Suit suit in Enum GetValues typeof Suit           The current accepted answer has a cast that I don t think  is needed  although I may be wrong

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Here is a working example of creating select options for a DDL   var resman   ViewModelResources TimeFrame ResourceManager   ViewBag TimeFrames   from MapOverlayTimeFrames timeFrame       in Enum GetValues typeof MapOverlayTimeFrames         select new SelectListItem                  Value   timeFrame ToString             Text   resman GetString timeFrame ToString       timeFrame ToString

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I think this is more efficient than other suggestions because GetValues   is not called each time you have a loop  It is also more concise  And you get a compile-time error  not a runtime exception if Suit is not an enum   EnumLoop lt Suit gt  ForEach  suit    gt        DoSomethingWith suit         EnumLoop has this completely generic definition   class EnumLoop lt Key gt  where Key   struct  IConvertible       static readonly Key   arr    Key   Enum GetValues typeof Key        static internal void ForEach Action lt Key gt  act            for  int i   0  i  lt  arr Length  i                  act arr i

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I use ToString   then split and parse the spit array in flags    Flags  public enum ABC      a   1     b   2     c   4     public IEnumerable lt ABC gt  Getselected  ABC flags       var values   flags ToString   Split          var enums   values Select x   gt   ABC Enum Parse typeof ABC   x Trim         return enums     ABC temp  ABC a   ABC b  var list   getSelected  temp   foreach  var item in list       Console WriteLine item ToString       ID      int item

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I do not hold the opinion this is better  or even good  I am just stating yet another solution  If enum values range strictly from 0 to n - 1  a generic alternative is  public void EnumerateEnum lt T gt          int length   Enum GetValues typeof T   Length      for  var i   0  i  lt  length  i                  var  enum    T  object i           If enum values are contiguous and you can provide the first and last element of the enum  then  public void EnumerateEnum         for  var i   Suit Spade  i  lt   Suit Diamond  i                  var  enum   i           But that s not strictly enumerating  just looping  The second method is much faster than any other approach though

[c#] How to enumerate an enum

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