in C# you define an Enum as you would normally do it:
using VL.Core; //required for the [Type] attribute
[Type] //this tells VL that this enum type is available
public enum MyEnum
how to get this into VL is descibed here:
but also not that this becomes much more easy in the upcoming alpha after the beta35.7 release.
also note that the above gives you the enumeration and the comparison nodes like = and != also IOBoxes will work with it. but these are the only nodes that will work with the enum. so to use the enum in a meaningful way you need some more logic, like checking for an entry with = and then place some code in an IF region if a enum value equals the entry...