Enums and Text Descriptions

[Kyle Novak]

What I want to do is take the values of an enum and have a related textual
description for each item. For example, if I have an enum declared as the
following...

[Flags]
public enum EqualityOperato r
{
Equal = 1,
LessThan = 2,
GreaterThan = 4,
BeginsWith = 8,
EndsWith = 16,
Contains = 32,
All = Equal | LessThan | GreaterThan | BeginsWith
| EndsWith | Contains
}

.... I want a related textual description of "Greater Than", "Begins With",
etc. I don't want to use the text description of "BeginsWith " (that's one
word) by calling this line of code...

string format = Enum.Format(typ eof(EqualityOpe rator),
EqualityOperato r.BeginsWith, "g"); //Returns "BeginsWith " - one word

Because I want this "object" to be data bindable, I guess I could use the
CollectionBase object. I'm just looking for other ways/opinions on how to
do this.

Thanks,

Kyle

[Brendan Grant]

One way, would be to use the [Description()] attribute (found within
System.Componen tModel before each tag, so your enum would end as:

[Flags]
public enum EqualityOperato r
{
[Description("Eq ual")]
Equal = 1,
[Description("Le ss Than")]
LessThan = 2,
[Description("Gr eater Than")]
GreaterThan = 4,
[Description("Be gins With")]
BeginsWith = 8,
[Description("En ds With")]
EndsWith = 16,
[Description("Co ntains")]
Contains = 32,
[Description("Al l")]
All = Equal | LessThan | GreaterThan | BeginsWith
| EndsWith | Contains
}

And every time you want the description, use the following function:

public static string GetEnumDescript ion(object value)
{
string retVal = "";
try
{
FieldInfo fieldInfo = value.GetType() .GetField(value .ToString());
DescriptionAttr ibute[] attributes =
(DescriptionAtt ribute[])fieldInfo.GetC ustomAttributes
(typeof(Descrip tionAttribute), false);
retVal =
((attributes.Le ngth>0)?attribu tes[0].Description:va lue.ToString()) ;
}
catch( NullReferenceEx ception )
{
//Occurs when we attempt to get description of an enum value
that does not exist
retVal = "Unknown";
}

return retVal;
}

Brendan
"Kyle Novak" wrote:

What I want to do is take the values of an enum and have a related textual
description for each item. For example, if I have an enum declared as the
following...

[Flags]
public enum EqualityOperato r
{
Equal = 1,
LessThan = 2,
GreaterThan = 4,
BeginsWith = 8,
EndsWith = 16,
Contains = 32,
All = Equal | LessThan | GreaterThan | BeginsWith
| EndsWith | Contains
}

.... I want a related textual description of "Greater Than", "Begins With",
etc. I don't want to use the text description of "BeginsWith " (that's one
word) by calling this line of code...

string format = Enum.Format(typ eof(EqualityOpe rator),
EqualityOperato r.BeginsWith, "g"); //Returns "BeginsWith " - one word

Because I want this "object" to be data bindable, I guess I could use the
CollectionBase object. I'm just looking for other ways/opinions on how to
do this.

Thanks,

Kyle

[Rodger Constandse]

Hi,

I've done something like this in my own project and it works very well. The only
downside is the run-time performance cost of using the reflection API to get at
the description. We ended up caching the descriptions after the first access
through the reflection API.

Best regards,

Rodger

Sequence Diagram Editor - Draw sequence diagrams faster
<http://www.SequenceDia gramEditor.com>
Brendan Grant wrote:

One way, would be to use the [Description()] attribute (found within
System.Componen tModel before each tag, so your enum would end as:

[Flags]
public enum EqualityOperato r
{
[Description("Eq ual")]
Equal = 1,
[Description("Le ss Than")]
LessThan = 2,
[Description("Gr eater Than")]
GreaterThan = 4,
[Description("Be gins With")]
BeginsWith = 8,
[Description("En ds With")]
EndsWith = 16,
[Description("Co ntains")]
Contains = 32,
[Description("Al l")]
All = Equal | LessThan | GreaterThan | BeginsWith
| EndsWith | Contains
}

And every time you want the description, use the following function:

public static string GetEnumDescript ion(object value)
{
string retVal = "";
try
{
FieldInfo fieldInfo = value.GetType() .GetField(value .ToString());
DescriptionAttr ibute[] attributes =
(DescriptionAtt ribute[])fieldInfo.GetC ustomAttributes
(typeof(Descrip tionAttribute), false);
retVal =
((attributes.Le ngth>0)?attribu tes[0].Description:va lue.ToString()) ;
}
catch( NullReferenceEx ception )
{
//Occurs when we attempt to get description of an enum value
that does not exist
retVal = "Unknown";
}

return retVal;
}

Brendan
"Kyle Novak" wrote:

What I want to do is take the values of an enum and have a related textual
description for each item. For example, if I have an enum declared as the
following.. .

[Flags]
public enum EqualityOperato r
{
Equal = 1,
LessThan = 2,
GreaterThan = 4,
BeginsWith = 8,
EndsWith = 16,
Contains = 32,
All = Equal | LessThan | GreaterThan | BeginsWith
| EndsWith | Contains
}

.... I want a related textual description of "Greater Than", "Begins With",
etc. I don't want to use the text description of "BeginsWith " (that's one
word) by calling this line of code...

string format = Enum.Format(typ eof(EqualityOpe rator),
EqualityOperato r.BeginsWith, "g"); //Returns "BeginsWith " - one word

Because I want this "object" to be data bindable, I guess I could use the
CollectionBas e object. I'm just looking for other ways/opinions on how to
do this.

Thanks,

Kyle