CachedDataItemEnumerator Class

Definition

public ref class CachedDataItemEnumerator sealed : System::Collections::Generic::IEnumerator<Microsoft::VisualStudio::Tools::Applications::CachedDataItem ^>

public sealed class CachedDataItemEnumerator : System.Collections.Generic.IEnumerator<Microsoft.VisualStudio.Tools.Applications.CachedDataItem>

type CachedDataItemEnumerator = class
    interface IEnumerator<CachedDataItem>
    interface IDisposable
    interface IEnumerator

Public NotInheritable Class CachedDataItemEnumerator
Implements IEnumerator(Of CachedDataItem)

Inheritance

Object

CachedDataItemEnumerator

Implements

IEnumerator<CachedDataItem> IEnumerator IDisposable

Remarks

Visual Basic and C# each contain a statement that hides the complexity of the enumerators (foreach in C# and For Each in Visual Basic). Use the appropriate statement for the language you are using, instead of directly manipulating the enumerator.

Enumerators can be used to read the data in the collection, but they cannot be used to modify the underlying collection.

Initially, the enumerator is positioned before the first element in the collection. The Reset method also brings the enumerator back to this position. At this position, setting the Current property throws an exception. Therefore, you must call the MoveNext method to advance the enumerator to the first element of the collection before reading the value of Current.

Current returns the same object until either MoveNext or Reset is called. MoveNext sets Current to the next element.

If MoveNext passes the end of the collection, the enumerator is positioned after the last element in the collection and MoveNext returns false. When the enumerator is at this position, subsequent calls to MoveNext also return false. If the last call to MoveNext returned false, calling Current throws an exception. To set Current to the first element of the collection again, you can call Reset followed by MoveNext.

An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated and the next call to MoveNext or Reset throws an InvalidOperationException. If the collection is modified between MoveNext and Current, Current returns the element that it is set to, even if the enumerator is already invalidated.

The enumerator does not have exclusive access to the collection; therefore, enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.

Properties

Methods

Explicit Interface Implementations

Applies to