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Biblioteca de clases de .NET Framework
IEnumerable (Interfaz)

Actualización: noviembre 2007

Expone el enumerador, que admite una iteración simple en una colección no genérica.

Espacio de nombres:  System.Collections [ http://msdn.microsoft.com/es-es/library/system.collections.aspx ]
Ensamblado:  mscorlib (en mscorlib.dll)
Visual Basic (Declaración)
<ComVisibleAttribute(True)> _
<GuidAttribute("496B0ABE-CDEE-11d3-88E8-00902754C43A")> _
Public Interface IEnumerable
Visual Basic (Uso)
Dim instance As IEnumerable
C#
[ComVisibleAttribute(true)]
[GuidAttribute("496B0ABE-CDEE-11d3-88E8-00902754C43A")]
public interface IEnumerable
Visual C++
[ComVisibleAttribute(true)]
[GuidAttribute(L"496B0ABE-CDEE-11d3-88E8-00902754C43A")]
public interface class IEnumerable
J#
/** @attribute ComVisibleAttribute(true) */
/** @attribute GuidAttribute("496B0ABE-CDEE-11d3-88E8-00902754C43A") */
public interface IEnumerable
JScript
public interface IEnumerable

Para obtener la versión genérica de esta interfaz, vea System.Collections.Generic..::.IEnumerable<(Of <(T>)>) [ http://msdn.microsoft.com/es-es/library/9eekhta0.aspx ] .

Notas para los implementadores:

Debe implementarse IEnumerable para admitir la semántica foreach de Microsoft Visual Basic. Las clases COM que permiten enumeradores también implementan esta interfaz.

En el ejemplo de código siguiente se muestra la implementación de las interfaces IEnumerable y IEnumerator [ http://msdn.microsoft.com/es-es/library/system.collections.ienumerator.aspx ] para una colección personalizada. En este ejemplo, no se llama explícitamente a los miembros de estas interfaces, pero se implementan para admitir el uso de foreach (For Each en Visual Basic) para recorrer en iteración la colección.

Visual Basic
Imports System
Imports System.Collections

Public Class Person

    Public Sub New(ByVal fName As String, ByVal lName As String)
        Me.firstName = fName
        Me.lastName = lName
    End Sub


    Public firstName As String
    Public lastName As String
End Class

Public Class People
    Implements IEnumerable

    Private _people() As Person

    Public Sub New(ByVal pArray() As Person)
        _people = New Person(pArray.Length - 1) {}

        Dim i As Integer
        For i = 0 To pArray.Length - 1
            _people(i) = pArray(i)
        Next i
    End Sub

    Public Function GetEnumerator() As IEnumerator _
      Implements IEnumerable.GetEnumerator

        Return New PeopleEnum(_people)
    End Function

End Class

Public Class PeopleEnum
    Implements IEnumerator

    Public _people() As Person

    ' Enumerators are positioned before the first element
    ' until the first MoveNext() call.
    Dim position As Integer = -1

    Public Sub New(ByVal list() As Person)
        _people = list
    End Sub

    Public Function MoveNext() As Boolean Implements IEnumerator.MoveNext
        position = position + 1
        Return (position < _people.Length)
    End Function

    Public Sub Reset() Implements IEnumerator.Reset
        position = -1
    End Sub

    Public ReadOnly Property Current() As Object Implements IEnumerator.Current
        Get
            Try
                Return _people(position)
            Catch ex As IndexOutOfRangeException
                Throw New InvalidOperationException()
            End Try
        End Get
    End Property
End Class

Class App
    Shared Sub Main()
        Dim peopleArray() As Person = { _
            New Person("John", "Smith"), _
            New Person("Jim", "Johnson"), _
            New Person("Sue", "Rabon")}

        Dim peopleList As New People(peopleArray)
        Dim p As Person
        For Each p In peopleList
            Console.WriteLine(p.firstName + " " + p.lastName)
        Next

    End Sub
End Class

' This code produces output similar to the following:
' 
' John Smith
' Jim Johnson
' Sue Rabon

C#
using System;
using System.Collections;

public class Person
{
    public Person(string fName, string lName)
    {
        this.firstName = fName;
        this.lastName = lName;
    }

    public string firstName;
    public string lastName;
}

public class People : IEnumerable
{
    private Person[] _people;
    public People(Person[] pArray)
    {
        _people = new Person[pArray.Length];

        for (int i = 0; i < pArray.Length; i++)
        {
            _people[i] = pArray[i];
        }
    }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return new PeopleEnum(_people);
        }
}

public class PeopleEnum : IEnumerator
{
    public Person[] _people;

    // Enumerators are positioned before the first element
    // until the first MoveNext() call.
    int position = -1;

    public PeopleEnum(Person[] list)
    {
        _people = list;
    }

    public bool MoveNext()
    {
        position++;
        return (position < _people.Length);
    }

    public void Reset()
    {
        position = -1;
    }

    public object Current
    {
        get
        {
            try
            {
                return _people[position];
            }
            catch (IndexOutOfRangeException)
            {
                throw new InvalidOperationException();
            }
        }
    }
}

class App
{
    static void Main()
    {
        Person[] peopleArray = new Person[3]
        {
            new Person("John", "Smith"),
            new Person("Jim", "Johnson"),
            new Person("Sue", "Rabon"),
        };

        People peopleList = new People(peopleArray);
        foreach (Person p in peopleList)
            Console.WriteLine(p.firstName + " " + p.lastName);

    }
}

/* This code produces output similar to the following:
 *
 * John Smith
 * Jim Johnson
 * Sue Rabon
 *
 */

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile para Smartphone, Windows Mobile para Pocket PC, Xbox 360

.NET Framework y .NET Compact Framework no admiten todas las versiones de cada plataforma. Para obtener una lista de las versiones compatibles, vea Requisitos de sistema de .NET Framework [ http://msdn.microsoft.com/es-es/library/8z6watww.aspx ] .

.NET Framework

Compatible con: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Compatible con: 3.5, 2.0, 1.0

XNA Framework

Compatible con: 2.0, 1.0

Referencia

IEnumerable (Miembros) [ http://msdn.microsoft.com/es-es/library/system.collections.ienumerable_members.aspx ]
System.Collections (Espacio de nombres) [ http://msdn.microsoft.com/es-es/library/system.collections.aspx ]
IEnumerator [ http://msdn.microsoft.com/es-es/library/system.collections.ienumerator.aspx ]
System.Collections.Generic..::.IEnumerable<(Of <(T>)>) [ http://msdn.microsoft.com/es-es/library/9eekhta0.aspx ]
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