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Mapping Text to Enum entries

, 6 Jun 2003
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Attaching a description to each entry in an enum.

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

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About the Author

Reto Ravasio

Switzerland Switzerland
No Biography provided

Comments and Discussions

 
GeneralMy vote of 5 Pin
lendres at 3-Apr-12 8:14
memberlendres3-Apr-12 8:14 
GeneralMy vote of 5 Pin
Dorofejev at 20-Dec-11 0:44
memberDorofejev20-Dec-11 0:44 
QuestionHow to use with dataset / tableadapter Pin
Saelen Kenny at 8-Nov-09 1:01
memberSaelen Kenny8-Nov-09 1:01 
QuestionQuery regarding description Tag in Enum Pin
NITINKADAM at 24-Nov-08 6:14
memberNITINKADAM24-Nov-08 6:14 
GeneralAwesome - thanks! Pin
935 at 22-Jun-07 6:48
member93522-Jun-07 6:48 
GeneralDifferent versions for speed improvements Pin
clementgatin at 12-Mar-07 12:37
memberclementgatin12-Mar-07 12:37 
GeneralThanks again Pin
Marc Clifton at 15-Oct-06 4:39
protectorMarc Clifton15-Oct-06 4:39 
GeneralSolution for C / C++ Pin
JimmyO at 5-May-05 10:56
memberJimmyO5-May-05 10:56 
GeneralRe: Solution for C / C++ Pin
Uwe Keim at 10-Apr-06 20:53
sitebuilderUwe Keim10-Apr-06 20:53 
Questionwhy??? Pin
koo9 at 18-Jan-05 11:53
memberkoo918-Jan-05 11:53 
AnswerRe: why??? Pin
Reto Ravasio at 19-Jan-05 9:36
memberReto Ravasio19-Jan-05 9:36 
QuestionWhat about Flags? Pin
Spliffy73 at 22-Mar-04 5:22
memberSpliffy7322-Mar-04 5:22 
AnswerRe: What about Flags? Pin
JSpens at 14-Aug-07 8:50
memberJSpens14-Aug-07 8:50 
AnswerRe: What about Flags? Pin
frinkfree at 11-Nov-08 13:55
memberfrinkfree11-Nov-08 13:55 
GeneralAutoDoc Pin
Dave Miller at 4-Feb-04 18:50
sussDave Miller4-Feb-04 18:50 
GeneralI liked this Pin
Palladino at 26-Aug-03 3:39
memberPalladino26-Aug-03 3:39 
QuestionWhat About using the System Enum Pin
vbnetuk at 25-Jun-03 23:10
membervbnetuk25-Jun-03 23:10 
AnswerRe: What About using the System Enum Pin
Reto Ravasio at 4-Jul-03 2:04
memberReto Ravasio4-Jul-03 2:04 
GeneralRe: What About using the System Enum Pin
vbnetuk at 6-Jul-03 22:05
membervbnetuk6-Jul-03 22:05 
GeneralRe: What About using the System Enum Pin
Reto Ravasio at 7-Jul-03 5:47
memberReto Ravasio7-Jul-03 5:47 
GeneralRe: What About using the System Enum Pin
devaulr at 6-Nov-03 3:40
memberdevaulr6-Nov-03 3:40 
GeneralRe: What About using the System Enum Pin
datavalue at 19-Oct-05 4:06
memberdatavalue19-Oct-05 4:06 
AnswerRe: What About using the System Enum Pin
ConradC at 1-Feb-05 9:22
memberConradC1-Feb-05 9:22 
GeneralMultilingual Pin
Uwe Keim at 7-Jun-03 22:36
sitebuilderUwe Keim7-Jun-03 22:36 
GeneralRe: Multilingual Pin
Heath Stewart at 27-Oct-03 6:07
editorHeath Stewart27-Oct-03 6:07 
GeneralRe: Multilingual Pin
Uwe Keim at 7-Mar-05 20:28
sitebuilderUwe Keim7-Mar-05 20:28 
GeneralRe: Multilingual Pin
Craig Fisher at 30-Oct-07 10:18
memberCraig Fisher30-Oct-07 10:18 
GeneralThe descriptions will also show up in the property grid Pin
leppie at 7-Jun-03 11:07
memberleppie7-Jun-03 11:07 
GeneralRe: The descriptions will also show up in the property grid Pin
Reto Ravasio at 8-Jun-03 0:34
memberReto Ravasio8-Jun-03 0:34 

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