How to get C Enum description from value

Question

I have an enum with Description attributes like this   public enum MyEnum       Name1   1       Description  Here is another        HereIsAnother   2       Description  Last one        LastOne   3     I found this bit of code for retrieving the description based on an Enum  public static string GetEnumDescription Enum value        FieldInfo fi   value GetType   GetField value ToString          DescriptionAttribute   attributes   fi GetCustomAttributes typeof DescriptionAttribute   false  as DescriptionAttribute         if  attributes    null  amp  amp  attributes Any                  return attributes First   Description             return value ToString        This allows me to write code like   var myEnumDescriptions   from MyEnum n in Enum GetValues typeof MyEnum                            select new   ID    int n  Name   Enumerations GetEnumDescription n       What I want to do is if I know the enum value  e g  1  - how can I retrieve the description  In other words  how can I convert an integer into an  Enum value  to pass to my GetDescription method

User · Answer

I put the code together from the accepted answer in a generic extension method, so it could be used for all kinds of objects:

public static string DescriptionAttr<T>(this T source)
{
    FieldInfo fi = source.GetType().GetField(source.ToString());

    DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(
        typeof(DescriptionAttribute), false);

    if (attributes != null && attributes.Length > 0) return attributes[0].Description;
    else return source.ToString();
}

Using an enum like in the original post, or any other class whose property is decorated with the Description attribute, the code can be consumed like this:

string enumDesc = MyEnum.HereIsAnother.DescriptionAttr();
string classDesc = myInstance.SomeProperty.DescriptionAttr();

User · Answer

To make this easier to use  I wrote a generic extension   public static string ToDescription lt TEnum gt  this TEnum EnumValue  where TEnum   struct       return Enumerations GetEnumDescription  Enum  object   TEnum EnumValue        now I can write           MyEnum my   MyEnum HereIsAnother          string description   my ToDescription            System Diagnostics Debug Print description     Note  replace  Enumerations  above with your class name

User · Answer

int value   1  string description   Enumerations GetEnumDescription  MyEnum value     The default underlying data type for an enum in C  is an int  you can just cast it

User · Answer

Update  The Unconstrained Melody library is no longer maintained  Support was dropped in favour of Enums NET   In Enums NET you d use   string description     MyEnum value  AsString EnumFormat Description     Original post  I implemented this in a generic  type-safe way in Unconstrained Melody - you d use   string description   Enums GetDescription  MyEnum value     This    Ensures  with generic type constraints  that the value really is an enum value Avoids the boxing in your current solution Caches all the descriptions to avoid using reflection on every call Has a bunch of other methods  including the ability to parse the value from the description   I realise the core answer was just the cast from an int to MyEnum  but if you re doing a lot of enum work it s worth thinking about using Unconstrained Melody

User · Answer

You can t easily do this in a generic way  you can only convert an integer to a specific type of enum   As Nicholas has shown  this is a trivial cast if you only care about one kind of enum  but if you want to write a generic method that can handle different kinds of enums  things get a bit more complicated   You want a method along the lines of   public static string GetEnumDescription lt TEnum gt  int value      return GetEnumDescription  Enum   TEnum value        error      but this results in a compiler error that  int can t be converted to TEnum   and if you work around this  that  TEnum can t be converted to Enum     So you need to fool the compiler by inserting casts to object   public static string GetEnumDescription lt TEnum gt  int value      return GetEnumDescription  Enum  object   TEnum  object value        ugly  but works     You can now call this to get a description for whatever type of enum is at hand   GetEnumDescription lt MyEnum gt  1   GetEnumDescription lt YourEnum gt  2

[c#] How to get C# Enum description from value?

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