Enumerator Implementation: Use struct or class?

Question

I noticed that List defines its enumerator as a struct, while ArrayList defines its enumerator as a class. What\'s t

Answer 1

The easiest way to write an enumerator in C# is with the "yield return" pattern. For example.

public IEnumerator<int> Example() {
  yield return 1;
  yield return 2;
}

This pattern will generate all of the enumerator code under the hood. This takes the decision out of your hands.

Answer 2

Write it using yield return.

As to why you might otherwise choose between class or struct, if you make it a struct then it gets boxed as soon as it is returned as an interface, so making it a struct just causes additional copying to take place. Can't see the point of that!