如果只在运行时知道枚举类型，如何枚举枚举？

Question

I found this answer on stackoverflow to enumerate an enum of a certain type:

var values = (SomeType[])Enum.GetValues(typeof(SomeType));

This works perfectly if i hard-code the enum type. But I need to be able to set the type in run time. i tried the following but this doesn't work:

var values = (typeof(T)[])Enum.GetValues(typeof(T));

Answer 1

typeof(T) will generally return you a Type object, so compiler thinks you want to apply indexing to that object.

Try using:

Enum.GetValues(typeof(T)).Cast<T>()

Answer 2

public static IEnumerable<T> GetValues<T>()
{
    return Enum.GetValues(typeof(T)).Cast<T>();
}

See fiddle

Answer 3

You can use the Cast<T>() method for result custing and the typeof(T).IsEnum method for type checking ( T must be an enumerated type).

The target method:

public static IEnumerable<T> GetValues<T>()
{
  if (!typeof(T).IsEnum) 
    throw new ArgumentException("T must be an enumerated type");
  return Enum.GetValues(typeof(T)).Cast<T>();
}

Usage example:

public enum EnumFoo
{
  Foo1, Foo2
}
public enum EnumBar
{
  Bar1, Bar2
}
public void Main()
{
  foreach (var value in GetValues<EnumFoo>())
    Console.WriteLine(value); // Foo1 Foo2
  foreach (var value in GetValues<EnumBar>())
    Console.WriteLine(value); // Bar1 Bar2
}

Answer 4

Your T is already of type Type . There is no need to use another typeof . A simple cast to a T[] should suffice:

T[] values = (T[]) Enum.GetValues(typeof(T));