What is the default value for enum variable

Question

An enum variable  anyone know if it is always defaulting to the first element

User · Answer

I think it s quite dangerous to rely on the order of the values in a enum and to assume that the first is always the default  This would be good practice if you are concerned about protecting the default value   enum E       Foo   0  Bar  Baz  Quux     Otherwise  all it takes is a careless refactor of the order and you ve got a completely different default

User · Answer

You can use this snippet  -D using System  using System Reflection   public static class EnumUtils       public static T GetDefaultValue lt T gt            where T   struct  Enum               return  T GetDefaultValue typeof T               public static object GetDefaultValue Type enumType                var attribute   enumType GetCustomAttribute lt DefaultValueAttribute gt  inherit  false           if  attribute    null              return attribute Value           var innerType   enumType GetEnumUnderlyingType            var zero   Activator CreateInstance innerType           if  enumType IsEnumDefined zero               return zero           var values   enumType GetEnumValues            return values GetValue 0            Example  using System   public enum Enum1       Foo      Bar      Baz      Quux   public enum Enum2       Foo    1      Bar    2      Baz    3      Quux   0   public enum Enum3       Foo    1      Bar    2      Baz    3      Quux   4    DefaultValue Enum4 Bar   public enum Enum4       Foo    1      Bar    2      Baz    3      Quux   4    public static class Program        public static void Main                  var defaultValue1   EnumUtils GetDefaultValue lt Enum1 gt             Console WriteLine defaultValue1      Foo          var defaultValue2   EnumUtils GetDefaultValue lt Enum2 gt             Console WriteLine defaultValue2      Quux          var defaultValue3   EnumUtils GetDefaultValue lt Enum3 gt             Console WriteLine defaultValue3      Foo          var defaultValue4   EnumUtils GetDefaultValue lt Enum4 gt             Console WriteLine defaultValue4      Bar

User · Answer

It is whatever member of the enumeration represents the value 0  Specifically  from the documentation      The default value of an enum E is the value produced by the expression  E 0    As an example  take the following enum   enum E       Foo  Bar  Baz  Quux     Without overriding the default values  printing default E  returns Foo since it s the first-occurring element   However  it is not always the case that 0 of an enum is represented by the first member  For example  if you do this   enum F          Give each element a custom value     Foo   1  Bar   2  Baz   3  Quux   0     Printing default F  will give you Quux  not Foo   If none of the elements in an enum G correspond to 0   enum G       Foo   1  Bar   2  Baz   3  Quux   4     default G  returns literally 0  although its type remains as G  as quoted by the docs above  a cast to the given enum type

[c#] What is the default value for enum variable?

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