What is Ienumerable.Getenumerator in C#?

Question

I was reading this documentation and I came across the following piece of code within a class that implements IEnumerable:

// Implementation for the GetEnumerator method.
IEnumerator IEnumerable.GetEnumerator()
{
    return (IEnumerator) GetEnumerator();
}

But what exactly is this IEnumerable.GetEnumerator? I know that IEnumerable is an interface, but there GetEnumerator would be a property of that interface?

The doubt was because usually put the name of the method in the place where it is IEnumerable.GetEnumerator. In that sense, I see the name of a method as something concrete, then how could an "interface property" play this role? It would be something like a special name?

Answer 1

GetEnumerator() ends with parentheses, right? And if you have this, as in all languages, it would be a... method!

What seems strange is having a surname in the method. And this is what is called explicit implementation of interface. It is a special way to name the implementation as it shows details in link.

Today it can be written like this:

IEnumerator IEnumerable.GetEnumerator() => (IEnumerator)GetEnumerator();

We have here the type of return, the name of the method preceded by which is the interface he is making the implementation, which differentiates from the standard implementation of the type itself, and then the body that just calls another existing method in the class making a cast to make the return of this method compatible.

If it did not break compatibility every enumeration system of C# would be redone, has errors in the whole idea, is one of the biggest problems of the language, and that most people do not even notice.