Can't Figure Out How To Implement IEnumerable T

Question

I have no problem implementing IEnumerable but can't figure out how to implement IEnumerable<T>. Using the non-generic ArrayList, I have this code:
class PeopleCollection : IEnumerable
ArrayList people = new ArrayList();
public PeopleCollection() { }
public IEnumerator GetEnumerator()
return people.GetEnumerator();
class Program
static void Main(string[] args)
PeopleCollection collection = new PeopleCollection();
foreach (Person p in collection)
Console.WriteLine(p);
I'm trying to do the same thing (using a List<Person> as the member variable instead of ArrayList) but get compile errors involving improper return types on my GetEnumerator() method. I start out with this:
class PeopleCollection : IEnumerable<Person>
List<Person> myPeople = new List<Person>();
public PeopleCollection() { }
public IEnumerator<Person> GetEnumerator()
throw new NotImplementedException();
IEnumerator IEnumerable.GetEnumerator()
throw new NotImplementedException();
class Program
static void Main(string[] args)
// Create a PeopleCollection object.
PeopleCollection peopleCollection = new PeopleCollection();
// Iterate over the collection.
foreach (Person p in peopleCollection)
Console.WriteLine(p);
Console.ReadLine();
That code compiles (basically because I haven't really done anything yet), but I get compile errors when I try to implement the GetEnumerator() methods.

Answer 1

The List<T> class implements the IEnumerable<T> interface, so your enumerator can return the GetEnumerator call from the list.
class PeopleCollection : IEnumerable<Person>
List<Person> myPeople = new List<Person>();
public PeopleCollection() { }
public IEnumerator<Person> GetEnumerator()
return myPeople.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator()
return myPeople.GetEnumerator();
class Program
static void Main(string[] args)
// Create a PeopleCollection object.
PeopleCollection peopleCollection = new PeopleCollection();
// Iterate over the collection.
foreach (Person p in peopleCollection)
Console.WriteLine(p);
Console.ReadLine();