Information Technology Reference
In-Depth Information
The IEnumerator<T> Interface
The
IEnumerator<T>
interface uses generics to return an actual derived type, rather than an
object of type
object
.
The
IEnumerator<T>
interface derives from two other interfaces: the non-generic
IEnumerator
interface and the
IDisposable
interface. It must therefore implement their
members.
You have already seen the non-generic
IEnumerator
interface and its three members.
The
IDisposable
interface has a single,
void
, parameterless method called
Dispose
,
which can be used to free unmanaged resources being held by the class.
The
IEnumerator<T>
interface itself has a single method,
Current
, which returns an item
of a derived type—
not
an item of type
object
.
Since both
IEnumerator<T>
and
IEnumerator
have a member named
Current
, you should
explicitly implement the
IEnumerator
version, and implement the generic version in the
class itself, as shown in Figure 20-6.
Figure 20-6 illustrates the implementation of the interface.
Figure 20-6.
Implementing the IEnumerator<T> interface
The declaration of the class implementing the interface should look something like the
pattern in the following code, where
T
is the type returned by the enumerator.
