About interface Enumerable and IEnumerator

[Tony]

Hello!

Interface IEnumerable consist of method GetEnumerator() which will return an
object of type IEnumerator.

Now to my question will every object that GetEnumerator return implement
Current, MoveNext and Reset.
I mean in this case I don't have to implement these three methods because
they are already accessible in the object that is returned from
GetEnumerator.

Is this correct understood ?

//Tony

[Marc Gravell]

Re: About interface Enumerable and IEnumerator

I mean in this case I don't have to implement these three methods because

they are already accessible in the object that is returned from
GetEnumerator.

If you are writing your own iterator, then yes - they must be implemented
(either explicit or implicit implementation is fine).

However, in C# 2 and above, a lot of this is done for you via "yield
return"; this makes creating iterators very painless.

Marc

[Jon Skeet [C# MVP]]

Re: About interface Enumerable and IEnumerator

On Feb 28, 2:25 pm, "Tony" <johansson.ande rs...@telia.com wrote:

Interface IEnumerable consist of method GetEnumerator() which will return an
object of type IEnumerator.
>
Now to my question will every object that GetEnumerator return implement
Current, MoveNext and Reset.

Yes, otherwise that wouldn't be implementing IEnumerator.

I mean in this case I don't have to implement these three methods because
they are already accessible in the object that is returned from
GetEnumerator.
>
Is this correct understood ?

It's hard to understand exactly what you mean. If you're *calling*
GetEnumerator() then you're using someone else's implementation to
start with - you wouldn't be implementing them in the first place.

What problem are you trying to solve?

Jon

[Tony]

Re: About interface Enumerable and IEnumerator

Hello!

In this example I don't have to implement the three method that
GetEnumerator returns. Do you mean that this is the most common situation
that you don't have to implement these three methods?

I didn't fully understood what you meant in the previous answer.

Person[] array =
{
new Person("532513-1234", "Olle", 34),
new Person("123456-4321", "Pelle", 12),
new Person("987654-5678", "Stina", 44)
};

public Form1()
{
IEnumerator iter = array.GetEnumer ator();

while (iter.MoveNext( ))
Console.WriteLi ne(iter.Current );
...
}

//Tony

"Marc Gravell" <marc.gravell@g mail.comskrev i meddelandet
news:O3mUYaheIH A.5296@TK2MSFTN GP05.phx.gbl...

I mean in this case I don't have to implement these three methods

because

they are already accessible in the object that is returned from
GetEnumerator.

>
If you are writing your own iterator, then yes - they must be implemented
(either explicit or implicit implementation is fine).
>
However, in C# 2 and above, a lot of this is done for you via "yield
return"; this makes creating iterators very painless.
>
Marc
>
>