Classe BreakpointTargetEnumerator

Gerarchia di ereditarietà

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

Sintassi

'Dichiarazione
Public NotInheritable Class BreakpointTargetEnumerator _
    Inherits DtsEnumerator
'Utilizzo
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

Proprietà

	Nome	Descrizione
	Current	Gets the current BreakpointTarget object in the collection.

In alto

Metodi

	Nome	Descrizione
	Equals	Ereditato da Object.
	Finalize	Ereditato da Object.
	GetHashCode	Ereditato da Object.
	GetType	Ereditato da Object.
	MemberwiseClone	Ereditato da Object.
	MoveNext	Advances the enumerator to the next element of the collection. Ereditato da DtsEnumerator.
	Reset	Sets the enumerator to its initial position, which is before the first element in the collection. Ereditato da DtsEnumerator.
	ToString	Ereditato da Object.

In alto

Osservazioni

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.

Protezione dei thread

I membri static (Shared in Visual Basic) pubblici di questo tipo sono affidabili. Non è invece garantita la sicurezza dei membri dell'istanza.

Vedere anche

Riferimento