MSDN Library

CachedDataHostItemEnumerator Class (2007 System)

Iterates through a CachedDataHostItemCollection.

Namespace:  Microsoft.VisualStudio.Tools.Applications
Assembly:  Microsoft.VisualStudio.Tools.Applications.ServerDocument.v9.0 (in Microsoft.VisualStudio.Tools.Applications.ServerDocument.v9.0.dll)

[PermissionSetAttribute(SecurityAction.Demand, Name = "FullTrust")]
public sealed class CachedDataHostItemEnumerator : IEnumerator<CachedDataHostItem>, 
	IDisposable, IEnumerator

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.


This class can be used only with solutions for Microsoft Office Word 2007 and Microsoft Office Excel 2007. To access the cached data in solutions for Word 2003 and Excel 2003, use the CachedDataHostItemEnumerator class in the Microsoft.VisualStudio.Tools.Applications.Runtime namespace in the Visual Studio 2005 Tools for Office Second Edition runtime. For more information, see Managing Documents on a Server by Using the ServerDocument Class.

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.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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