How do I declare a nested enum?

Question

I want to declare a nested enum like:

\\\\pseudocode
public enum Animal
{
  dog = 0,
  cat = 1
}

private enum dog
{
   bulldog = 0,
   greyhound = 1,
   hus         


        

Answer 1

I would probably use a combination of enumerated bit fields and extension methods to achieve this. For example:

public enum Animal
{
   None = 0x00000000,
   AnimalTypeMask = 0xFFFF0000,
   Dog = 0x00010000,
   Cat = 0x00020000,
   Alsation = Dog | 0x00000001,
   Greyhound = Dog | 0x00000002,
   Siamese = Cat | 0x00000001
}

public static class AnimalExtensions
{
  public bool IsAKindOf(this Animal animal, Animal type)
  {
    return (((int)animal) & AnimalTypeMask) == (int)type);
  }
}

Update
In .NET 4, you can use the Enum.HasFlag method rather than roll your own extension.