BreakpointTargetEnumerator Class

项目
12/15/2008

Creates a BreakpointTargetEnumerator for the BreakpointTargets collection. This class cannot be inherited.

命名空间: Microsoft.SqlServer.Dts.Runtime
程序集: Microsoft.SqlServer.ManagedDTS (in microsoft.sqlserver.manageddts.dll)

语法

声明
Public NotInheritable Class BreakpointTargetEnumerator
    Inherits DtsEnumerator

public sealed class BreakpointTargetEnumerator : DtsEnumerator

public ref class BreakpointTargetEnumerator sealed : public DtsEnumerator

public final class BreakpointTargetEnumerator extends DtsEnumerator

public final class BreakpointTargetEnumerator extends DtsEnumerator

备注

Enumerators only enable reading the data in the collection. Enumerators 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, calling the Current property throws an exception. Therefore, you must call 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.

After the end of the collection is passed, the enumerator is positioned after the last element in the collection, and calling MoveNext returns 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 invalidated and becomes irrecoverable; thus the next call to MoveNext or Reset throws an InvalidOperationException. However, if the collection is modified between MoveNext and Current, Current will return the element that it is set to, even if the enumerator has been invalidated.

The enumerator does not have exclusive access to the collection; therefore, enumerating through a collection is not a thread-safe procedure. Even when a collection is synchronized, other threads could 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.

Inheritance Hierarchy

System.Object
Microsoft.SqlServer.Dts.Runtime.DtsEnumerator
Microsoft.SqlServer.Dts.Runtime.BreakpointTargetEnumerator

线程安全

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

平台

开发平台

有关支持的平台列表，请参阅安装 SQL Server 2005 的硬件和软件要求。

目标平台