Clase DtsEnumerator

Artículo
04/26/2013

Defines an abstract base class that implements the IEnumerator methods.

Jerarquía de herencia

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

Espacio de nombres: Microsoft.SqlServer.Dts.Runtime
Ensamblado: Microsoft.SqlServer.ManagedDTS (en Microsoft.SqlServer.ManagedDTS.dll)

Sintaxis

'Declaración
Public MustInherit Class DtsEnumerator _
    Implements IEnumerator
'Uso
Dim instance As DtsEnumerator

public abstract class DtsEnumerator : IEnumerator

public ref class DtsEnumerator abstract : IEnumerator

[<AbstractClassAttribute>]
type DtsEnumerator =  
    class 
        interface IEnumerator 
    end

public abstract class DtsEnumerator implements IEnumerator

El tipo DtsEnumerator expone los siguientes miembros.

Constructores

	Nombre	Descripción
	DtsEnumerator	Initializes a new instance of the DtsEnumerator class.

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Propiedades

	Nombre	Descripción
	Current	Gets the current element in the collection.

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Métodos

	Nombre	Descripción
	Equals	(Se hereda de Object.)
	Finalize	(Se hereda de Object.)
	GetHashCode	(Se hereda de Object.)
	GetType	(Se hereda de Object.)
	MemberwiseClone	(Se hereda de Object.)
	MoveNext	Advances the enumerator to the next element of the collection.
	Reset	Sets the enumerator to its initial position, which is before the first element in the collection.
	ToString	(Se hereda de Object.)

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Comentarios

DtsEnumerator is the base interface for all enumerators. The DtsEnumerator allows only reading of the data in the collection and is not used to modify the underlying collection.

Initially, the enumerator is positioned before the first element in the collection. Reset also brings the enumerator back to this position. At this position, calling Current throws an exception. Therefore, you must call MoveNext 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 irrecoverably invalidated and the next call to MoveNext or Reset throws an InvalidOperationException. If the collection is modified between MoveNext and Current, Current will return 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 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 lock the collection during the entire enumeration or catch the exceptions that result from changes made by other threads.

Ejemplos

The following code example adds a task to a package then runs the package. The warnings collection is shown by creating a WarningEnumerator, which inherits from this DtsEnumerator class, and displays each warning description.

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SqlServer.Dts.Runtime;
using Microsoft.SqlServer.Dts.Tasks.ExecuteSQLTask;

namespace Microsoft.SqlServer.SSIS.Samples
{
    class Program
    {
        static void Main(string[] args)
        {
            Package package = new Package();
            Console.WriteLine("Package warnings count before running: {0}", package.Warnings.Count);

            TaskHost taskH2 = (TaskHost)package.Executables.Add("STOCK:SendMailTask");
            taskH2.FailPackageOnFailure = false;
            taskH2.FailParentOnFailure = false;
            Console.WriteLine("SendMailTask: {0}", taskH2.ID);
 
            // Test that warnings were successfully added to the collection.
            package.MaximumErrorCount = 100;
            package.FailPackageOnFailure = false;
            package.FailParentOnFailure = false;
            package.DelayValidation = true;
            package.Execute();

            Console.WriteLine("Package warnings count after running the package: {0}", package.Warnings.Count);

            // Create the enumerator.
            WarningEnumerator myEnumerator = package.Warnings.GetEnumerator();
            Console.WriteLine("The collection contains the following values:");
            int i = 0;
            while ((myEnumerator.MoveNext()) && (myEnumerator.Current != null))
                Console.WriteLine("[{0}] {1}", i++, myEnumerator.Current.Description);
        }
    }
}

Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Microsoft.SqlServer.Dts.Runtime
Imports Microsoft.SqlServer.Dts.Tasks.ExecuteSQLTask
 
Namespace Microsoft.SqlServer.SSIS.Samples
    Class Program
        Shared  Sub Main(ByVal args() As String)
            Dim package As Package =  New Package() 
            Console.WriteLine("Package warnings count before running: {0}", package.Warnings.Count)
 
            Dim taskH2 As TaskHost = CType(package.Executables.Add("STOCK:SendMailTask"), TaskHost)
            taskH2.FailPackageOnFailure = False
            taskH2.FailParentOnFailure = False
            Console.WriteLine("SendMailTask: {0}", taskH2.ID)
 
            ' Test that warnings were successfully added to the collection.
            package.MaximumErrorCount = 100
            package.FailPackageOnFailure = False
            package.FailParentOnFailure = False
            package.DelayValidation = True
            package.Execute()
 
            Console.WriteLine("Package warnings count after running the package: {0}", package.Warnings.Count)
 
            ' Create the enumerator.
            Dim myEnumerator As WarningEnumerator =  package.Warnings.GetEnumerator() 
            Console.WriteLine("The collection contains the following values:")
            Dim i As Integer =  0 
            While (myEnumerator.MoveNext()) &&(myEnumerator.Current <> Nothing)
                Console.WriteLine("[{0}] {1}",i = Console.WriteLine("[{0}] {1}",i + 1
            End While
        End Sub
    End Class
End Namespace

Sample Output:

Package warnings count before running: 0

SendMailTask: {34CAEFF9-64BF-401D-B646-C88B705DB971}

Package warnings count after running the package: 2

The collection contains the following values:

[0] The address in the From line is not formed correctly. It is missing an @ or it is not valid.

[1] Subject is empty

Seguridad para subprocesos

Cualquier miembro público static (Shared en Visual Basic) de este tipo es seguro para subprocesos. No se garantiza que los miembros de instancia sean seguros para subprocesos.

Vea también

Referencia

Espacio de nombres Microsoft.SqlServer.Dts.Runtime

Jerarquía de herencia

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Clase DtsEnumerator

Jerarquía de herencia

Sintaxis

Constructores

Propiedades

Métodos

Comentarios

Ejemplos

Seguridad para subprocesos

Vea también

Referencia

Jerarquía de herencia

Recursos adicionales