Artikel
05/23/2011

BreakpointTargetEnumerator Class

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

Inheritance Hierarchy

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

Namespace: Microsoft.SqlServer.Dts.Runtime
Assembly: Microsoft.SqlServer.ManagedDTS (in Microsoft.SqlServer.ManagedDTS.dll)

Syntax

'Declaration
Public NotInheritable Class BreakpointTargetEnumerator _
    Inherits DtsEnumerator
'Usage
Dim instance As BreakpointTargetEnumerator

public sealed class BreakpointTargetEnumerator : DtsEnumerator

public ref class BreakpointTargetEnumerator sealed : public DtsEnumerator

[<SealedAttribute>]
type BreakpointTargetEnumerator =  
    class
        inherit DtsEnumerator
    end

public final class BreakpointTargetEnumerator extends DtsEnumerator

The BreakpointTargetEnumerator type exposes the following members.

Properties

	Name	Description
	Current	Gets the current BreakpointTarget object in the collection.

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Methods

	Name	Description
	Equals	(Inherited from Object.)
	Finalize	(Inherited from Object.)
	GetHashCode	(Inherited from Object.)
	GetType	(Inherited from Object.)
	MemberwiseClone	(Inherited from Object.)
	MoveNext	Advances the enumerator to the next element of the collection. (Inherited from DtsEnumerator.)
	Reset	Sets the enumerator to its initial position, which is before the first element in the collection. (Inherited from DtsEnumerator.)
	ToString	(Inherited from Object.)

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Remarks

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.

Thread Safety

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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