Exceptions

Type	Reason
InvalidOperationException	The collection was modified after the enumerator was instantiated. [Edit]

Remarks

Note: When the current instance is constructed or after IEnumerator.Reset is called, the current instance is positioned immediately before the first element of the collection, use IEnumerator.MoveNext to position the current instance over the first element of the collection.

Operation

A call to IEnumerator.Reset is required to position the current instance immediately before the first element of the collection. If elements are added, removed, or repositioned in the collection after the current instance was instantiated, it is required that a call to IEnumerator.Reset throw a InvalidOperationException.

Note to Inheritors

A call to IEnumerator.Reset can involve taking a new snapshot of the collection or simply moving to the beginning of the collection. The preferred implementation is to simply move the current instance to the beginning of the collection, before the first element. This invalidates the current instance if the collection has been modified since the current instance was constructed, which is consistent with IEnumerator.MoveNext and IEnumerator.Current.

Usage

Use the IEnumerator.MoveNext method to check if the current instance is positioned immediately past the last element of the collection, and to position it over the next element if it is not already past the last element of the collection.

[Edit]

Requirements

Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0