Using Objects Instead of Enumerations: ASP Alliance

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Using Objects Instead of Enumerations

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by Brendan Enrick
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Conclusion

For many people, an enumeration is the correct solution, and for others the solution is a lookup table. I do not think those should be used together, but some people might have a reason to do so. It is important to keep in mind the circumstances of your exact situation when deciding, because I think there are plenty of times when an object should be used instead of either one.

Using the method outlined in this article should allow you to get around using an enumeration or a lookup table. It is an alternative that lets you extend enumerations, and has some other pros and cons. In some ways they are not as easy to work with as enumerations, but they are also safer in some ways.

You can find more content from this author on his blog.

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User Comments

Title: good
Name: msoni
Date: 2010-01-05 8:31:11 AM
Comment:
i like it ......its a very nice aricle

Title: Good Article/Weak Arguments
Name: Clint
Date: 2009-03-25 2:13:49 PM
Comment:
Good article on the usage between objects/enumerators; weak arguments on the reasons. The statement "If there will be a good amount of logic based on these use an enumeration or an object. Do not have a lookup table. I know it is nice for the database, but any changes to the database will cause problems in the code." collapses on itself. Regardless of implementation, values that dictate logic will usually have a negative impact on the coded logic.

Title: Great!!!
Name: Gourik Kumar Bora
Date: 2009-02-20 2:07:39 AM
Comment:
Hi Enrick!!!
This is really cool...
thanks a ton....

Title: Thanks
Name: Amir Arjmand
Date: 2009-02-18 7:48:28 PM
Comment:
Thanks Brendan,

Yes it did answer my question.

Title: RE: Two questions
Name: Brendan Enrick
Date: 2009-02-18 9:14:52 AM
Comment:
@Amir sorry about that. I am using a lambda expression in that code snippet.
http://msdn.microsoft.com/en-us/library/bb397687.aspx

Array.Find(items.ToArray(), instance => instance.Name == name);

Basically you can read this line like this, "find from items.ToArray() an item where that item's Name property is equal to the variable name".

The variable "instance" is defined at that point to represent any item in the array we are searching.

I hope that answers your questions.

Title: Two questions
Name: Amir Arjmand
Date: 2009-02-17 9:54:41 PM
Comment:
Hi everyone, I am new to C# and as I was going through the sample code, I came upon this statement

instance => instance.Name == Name

Could anyone please explain how exactlly this part of the code works. Where does that instance come from and what is => ? I could not find anything regarding that operator in msdn library for C#?

Thanks;

Title: RE: hmm
Name: Brendan Enrick
Date: 2009-02-17 8:50:19 AM
Comment:
@dario-g thank you for making sure I don't pass along misinformation. Although, there is a big difference between casting an integer as an enum and passing an out of range integer to this object. If you read the code listing 6 above, you will notice that the object throws an argument out of range exception if the integer is out of range. This means that you will know there is a problem and what the problem is. You can also easily handle this exception.

If you used the enum, you might not run into any exceptions, and maybe later the code will save the integer value of the enum. You are going to have an invalid result stored somewhere and possibly not even know.

Thank you for the comment. Feedback is always welcome and appreciated.

Title: Thank you
Name: Brendan Enrick
Date: 2009-02-17 8:43:40 AM
Comment:
@Joydip Thank you. I am glad you liked the article.

Title: Mousover
Name: Brendan Enrick
Date: 2009-02-17 8:42:47 AM
Comment:
@Alex Simkin Yes, you are right the debugger works very well with enumerations. However, if you move the mouse a little bit more to the plus sign, it will reveal the values of the properties of this object. This will give you access to not just the name, but also the value of the object. This is more than you would get from an enum.

Title: Mr. ?
Name: Alex Simkin
Date: 2009-02-16 2:35:11 PM
Comment:
In debugger, if you mouseover variable of enum type, you will find out the value instantly. If you mouseover MyObject variable, you will only see that it contains MyObject instance.

Title: Author and ASP.NET MVP
Name: Joydip Kanjilal
Date: 2009-02-16 10:59:03 AM
Comment:
Excellent article! Keep posting such awesome articles.

Thanks,

Joydip

Title: hmm
Name: dario-g
Date: 2009-02-16 3:34:56 AM
Comment:
MyObject obj = ...FromId(10); // This is a really bad dangerous thing that can happen

No difference.