Question

I am learning about implementing interfaces and generics, I made this code, but VStudio says that I did not implement System.Collections.Enumerable.GetEnumerator().
Did I not do this below, generically? It wants two implementations?

namespace Generic_cars
{
 class VehicleLot:IEnumerable<Vehicle>
 {
    public List<Vehicle> Lot = new List<Vehicle>();

    IEnumerator<Vehicle> IEnumerable<Vehicle>.GetEnumerator()
    {
        foreach (Vehicle v in Lot) { yield return v; };
    }
 }
}

Answer 1

You are implementing IEnumerable<Vehicle>, a generic interface that is strongly typed to hold Vehicle objects. That interface, however, derives from the older IEnumerable interace that is not generic, and is typed to hold object objects.

If you want to implement the generic version (which you do) you need to also implement the non-generic version. Typically you would implement the non-generic GetEnumerator by simply calling the generic version.

Also, you probably don’t want to be explicitly implementing GetEnumerator<Vehicle> the way you are; that will require you to explicitly cast your objects to IEnumerable<Vehicle> in order to use them. Instead, you probably want to do this:

public IEnumerator<Vehicle> GetEnumerator() {
    foreach( Vehicle item in items ) {
        yield return item;
    }
}

IEnumerator IEnumerable.GetEnumerator() {
    return GetEnumerator();
}