<!-- Article image -->
<!-- Add the rest of your HTML here -->
C# enums are a quite powerful element of the C# language. Because of its metadata stored in the assembly
they provide us with much more info than their equivalent in C++. What´s more, using
System.Reflection.Emit we can delay
the creation of an enum till runtime.
Using the code
In C# (as in C++) every instance of an enum type takes 4 bytes in memory (only the integer value associated to
the string value is stored), you can use
sizeof to verify this, so it´s a really storage efficient data structure. The great thing in C# is that for
every enum class in our code the string values are stored in the assembly as metadata, so we can access to
it in our code. We can use for it methods like
Enum.GetNames(). Here´s a little sample:
public static void Main()
Console.WriteLine("Write the number of the selected Language");
Console.WriteLine(i + "." + langAr[i]);
Console.WriteLine("Your Language of choice is: " + myLang);
Another great thing about C# enums is that we can create an enum class in runtime, after the users have
fed our program with data. In the following sample we want an enum with the months that our business offers
to our employees to choose as holidays month. The problem is that we don´t know till runtime which months we
are going to offer to our employees. System.Reflection.Emit comes in our help.
First we fill a string with the source code for the new enum (Holidays), then we write it to disk and compile it. Finally we
load the new assembly. Since that moment we can work with the new enum we´ve coded, and we can create instances
of that new enum. One useful method we need to assign values to the instances of our new enum class is
Here it´s how it works:
Employee emp=new Employee();
Console.WriteLine("Insert Employee data");
For this sample I make use of a small, incomplete and untested Library (ReflectiveTools)
that I´ve coded to make easier some of the most common reflection operations (saving
dynamic code to disk and compiling it). This library is included in the zip file.
Well, I think you have to download the source code to really understand the purpose
of this article.
I hope this article to be an example of how useful C# enums can be.
I really can´t understand why languages like Java have excluded enums of the
One last thing, some of the comments in the source code are written in Spanish,
I´m sorry, but that´s my native language. Anyway I don´t think those comments
are too important.
- 04/04/2003: This article is submitted to CodeProject