Question

In C#, can you use number ranges in enum types, for example

public enum BookType
{
    Novel = 1,
    Journal = 2,
    Reference = 3,
    TextBook = 4 .. 10
}

EDIT: The reason this is needed is to cast from a number to the enum type, eg:

int iBook = 5
BookType btBook = (BookType)ibook
Debug.Print "Book " + ibook + " is a " btBook

and the expected output is: Book 5 is a TextBook

Answer 1

According to the C# standard (p612, The C# Programming Language) the value given to an enumeration must be a constant integer (or any similar type – long, byte, sbyte, short, etc), so a range of values isn’t valid.

My compiler (VS2008) agrees with the spec.

Since you can’t repeat names within an enumeration, the closest you’ll get is something like this:

public enum BookType
{
    Novel = 1,
    Journal = 2,
    Reference = 3,
    TextBook4 = 4,
    TextBook5 = 5, ...
    TextBook10 = 10
}

Which is actually pretty ugly. Perhaps an enum is not the solution to your particular problem …