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First Posted 6 Jun 2003
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Mapping Text to Enum entries

By Reto Ravasio | 6 Jun 2003
Attaching a description to each entry in an enum.
3 votes, 5.1%
1
1 vote, 1.7%
2

3
10 votes, 16.9%
4
45 votes, 76.3%
5
4.83/5 - 59 votes
4 removed
μ 4.68, σa 1.74 [?]

Sample Image - EnumWithDescription.png

Introduction

While porting old C code to C#, I stumbled across lots of huge arrays which mapped constants to strings. While looking for the C# way of doing this, I discovered custom attributes and reflection.

How is it done?

Append a Description attribute to each enum entry:

private enum MyColors
{
   [Description("yuk!")]       LightGreen    = 0x012020,
   [Description("nice :-)")]   VeryDeepPink  = 0x123456,
   [Description("so what")]    InvisibleGray = 0x456730,
   [Description("no comment")] DeepestRed    = 0xfafafa,
   [Description("I give up")]  PitchBlack    = 0xffffff,
}

To access the description from code, the following function is called:

public static string GetDescription(Enum value)
{
   FieldInfo fi= value.GetType().GetField(value.ToString()); 
   DescriptionAttribute[] attributes = 
         (DescriptionAttribute[])fi.GetCustomAttributes(
         typeof(DescriptionAttribute), false);
   return (attributes.Length>0)?attributes[0].Description:value.ToString();
}

Without the following using declaration, the code will not compile.

using System.ComponentModel;        
using System.Reflection;

Benefits

Instead of having constants and huge arrays all over the code, the above solution keeps declarations and descriptions nicely together.

History

I've only found out by accident that the framework already provides a DescriptionAttribute class.

I built the first version with my own custom attribute and got conflicts when I started using the ComponentModel namespace.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Reto Ravasio



Switzerland Switzerland

Member


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GeneralMy vote of 5 PinmemberDorofejev0:44 20 Dec '11  
QuestionHow to use with dataset / tableadapter PinmemberSaelen Kenny1:01 8 Nov '09  
QuestionQuery regarding description Tag in Enum PinmemberNITINKADAM6:14 24 Nov '08  
GeneralAwesome - thanks! Pinmember9356:48 22 Jun '07  
GeneralDifferent versions for speed improvements Pinmemberclementgatin12:37 12 Mar '07  
GeneralThanks again PinsupporterMarc Clifton4:39 15 Oct '06  
GeneralSolution for C / C++ PinmemberJimmyO10:56 5 May '05  
GeneralRe: Solution for C / C++ PinsitebuilderUwe Keim20:53 10 Apr '06  
Questionwhy??? Pinmemberkoo911:53 18 Jan '05  
AnswerRe: why??? PinmemberReto Ravasio9:36 19 Jan '05  
QuestionWhat about Flags? PinmemberSpliffy735:22 22 Mar '04  
AnswerRe: What about Flags? PinmemberJSpens8:50 14 Aug '07  
AnswerRe: What about Flags? Pinmemberfrinkfree13:55 11 Nov '08  
GeneralAutoDoc PinsussDave Miller18:50 4 Feb '04  
GeneralI liked this PinmemberPalladino3:39 26 Aug '03  
QuestionWhat About using the System Enum Pinmembervbnetuk23:10 25 Jun '03  
AnswerRe: What About using the System Enum PinmemberReto Ravasio2:04 4 Jul '03  
GeneralRe: What About using the System Enum Pinmembervbnetuk22:05 6 Jul '03  
GeneralRe: What About using the System Enum PinmemberReto Ravasio5:47 7 Jul '03  
GeneralRe: What About using the System Enum Pinmemberdevaulr3:40 6 Nov '03  
GeneralRe: What About using the System Enum Pinmemberdatavalue4:06 19 Oct '05  
AnswerRe: What About using the System Enum PinmemberConradC9:22 1 Feb '05  
GeneralMultilingual PinsitebuilderUwe Keim22:36 7 Jun '03  
GeneralRe: Multilingual PineditorHeath Stewart6:07 27 Oct '03  
GeneralRe: Multilingual PinsitebuilderUwe Keim20:28 7 Mar '05  

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