Howto - C# enums with additional attributes (Java enum gaps covered)30 Jun 2012 Tags:
Disclaimer: This post isn’t going to be complete apple-to-apple and even apple-to-oranges comparison. It’s going to be describe-the-pain-and-solution post.
I originally come from Java world. You know, Java world is sunny, awesome and peaceful place. Ok, Ok, enough with trolling. I believe habits and experience is programmers bless and curse. We care it to ourselves whenever we switch platforms, teams, applications.
One thing I have used to in Java world - are enums. Not just some sort of numeric values (as C++ enums), but discrete set of immutable entities instead. It was a little bit shocking to me to find out C# (.Net) enums don’t support such concept.
For example, please take a look to this Java code snippet
And usage sample:
Let’s take another look into code snippets above and let’s write down some key points about Java enums.
- Enums inherit from
java.lang.Enumclass (not seen here, implicit thing)
- Enum values have ordinal (numeric) value. See
Enum#ordinal()for reference. (NB: you could specify it explicitly. If you need some sort of controlled numeric value, you should it yourselves the same manner I did it with htmlCode and rgbCode.
- Enum values have human readable name. See
- You are able to add as many additional attributes and behaviour to your enum type as you wish. In the sample above I’ve specified 2 additional attributes: rgb color and html color codes, as well as interface methods to fetch those from the enum instances.
So, to recap - Java enums are quite powerful and extensible beasts. I liked those and it was quite painful do not have them during my day/to day coding session in C#. You know the statement “if all you have is a hammer, everything looks like a nail”. And every damn problem seemed to be nailed by Java enum thing :) Every problems needs a solution though.
With a little (ok, won’t be so humble; with quite a lot actually) web-search help I found out I could use C# .Net annotations to provide additional attributes/semantics to C# code elements. Some reading, small experiments and vuala the following code has been born.
Let’s also provide sample usage code snippet.
To recap with C#/.Net enum solution.
- With a little coding help - it’s possible to provide additional attributes/semantics to enum values.
- There is still no an easy way to provide additional behavior to enum values.
However it’s still better than nothing :)
- C#/.Net is usable afterwards :)
- I still like Java enum thing and still think this is damn good nail for my hammer (maybe I just need to code C# much more longer to get it the other way).
It proved to be useless write. However you always feel better when you share your pain with others :)
NB. If you've found typos or errors, please suggest a correction or edit on github.