Enumeration As String

Question

enum ValidationMessages
{
    C01_OOHArrestRequired = "Test",
    Trivial,
    Regular,
    Important,
    Critical
};

I have the above code. I want to be able to create enums which I can use but are strings not integers.

This is so I can show same string in the UI for validation errors and then test for them in my unit tests and have the messages coming from the same place (been static).

But it says "Cannot convert string to int"

How to have enum as strings?

Then, don't use enums. Use a class with a bunch of constants. — Candide, Jan 30 '14 at 09:43
See this interesting question: http://stackoverflow.com/questions/424366/c-sharp-string-enums — Patrick Hofman, Jan 30 '14 at 09:43

score 3 · Accepted Answer · answered Jan 30 '14 at 09:43

3

You cannot have an enum of type string, as enums are value types (byte, sbyte, short, ushort, int, uint, long, or ulong).

Instead create a static class with const fields:

public static class CardiologyValidationMessages
{
    public const string C01_OOHArrestRequired = "OOH Arrest is required when 1 or more Procedures Performed has IsCoronary = True"
}

answered Jan 30 '14 at 09:43

Jakub Konecki

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Does this have roughly the same performance as ENUM? E.g. no major performance impact? – Lemex Jan 30 '14 at 09:48
1

No performance impact. Compiler may inline the strings the same way the enum values are inlined. You app has better places to improve performance than enum usages. – Jakub Konecki Jan 30 '14 at 09:49
Thanks! 100% Best/Simple answer. – Lemex Jan 30 '14 at 09:55
@LmC, of course, there are other benefits to an `Enum` but, if you don't need those, this is the way to go. – Jodrell Jan 30 '14 at 10:37
@Jodrell - what are the other benefits? – Jakub Konecki Jan 30 '14 at 10:41
An integer requires less storage than this and most strings. The items within an enum have an inherent orderability. – Jodrell Jan 30 '14 at 12:17
Is the context you've added to your answer just an inspired guess or is there an earlier question somewhere? – Jodrell Jan 30 '14 at 12:20
@Jodrell - That was the string in the first version of the question, it was edited later on I believe. – Jakub Konecki Jan 30 '14 at 12:21

score 1 · Answer 2 · answered Jan 30 '14 at 09:43

1

You can't. From MSDN:

The approved types for an enum are byte, sbyte, short, ushort, int, uint, long, or ulong.

What you can do is have a dictionary that maps an enum to an error message: Dictionary<CardiologyValidationMessages, string>

answered Jan 30 '14 at 09:43

dcastro

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Jodrell · Answer 3 · 2014-01-30T10:35:19.230

1

"An enumeration is a set of named constants whose underlying type is any integral type"

However, you could write a conversion function.

string ToValidationMessageString(ValidationMessage value)
{
    switch(value)
    {
        case C01_OOHArrestRequired:
            return "Test";

        default:
            return value.ToString();
    }
}

or some such.

edited Jan 30 '14 at 10:35

answered Jan 30 '14 at 09:48

Jodrell

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Richard · Answer 4 · 2014-01-30T09:49:51.127

Anyone know how to have enum as strings?

You cannot.

From the C# Language Specification Version 5 (supplied with Visual Studio 2013) section 4.1.9

An enumeration type is a distinct type with named constants. Every enumeration type has an underlying type, which must be byte, sbyte, short, ushort, int, uint, long or ulong.

However you can apply an DisplayAttribute with a name to the values of the enumeration and then use the usual reflection methods to get the name for a given value.

Enumeration As String

4 Answers4