IEnumerable Interfaz
Definición
Expone un enumerador, que admite una iteración simple en una colección no genérica.Exposes an enumerator, which supports a simple iteration over a non-generic collection.
public interface class IEnumerable
public interface IEnumerable
[System.Runtime.InteropServices.Guid("496B0ABE-CDEE-11d3-88E8-00902754C43A")]
public interface IEnumerable
[System.Runtime.InteropServices.Guid("496B0ABE-CDEE-11d3-88E8-00902754C43A")]
[System.Runtime.InteropServices.ComVisible(true)]
public interface IEnumerable
type IEnumerable = interface
[<System.Runtime.InteropServices.Guid("496B0ABE-CDEE-11d3-88E8-00902754C43A")>]
type IEnumerable = interface
[<System.Runtime.InteropServices.Guid("496B0ABE-CDEE-11d3-88E8-00902754C43A")>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type IEnumerable = interface
Public Interface IEnumerable
- Derivado
- Atributos
Ejemplos
En el ejemplo de código siguiente se muestra el procedimiento recomendado para recorrer en iteración una colección personalizada mediante la implementación de las IEnumerable IEnumerator interfaces y.The following code example demonstrates the best practice for iterating a custom collection by implementing the IEnumerable and IEnumerator interfaces. En este ejemplo, no se llama a los miembros de estas interfaces explícitamente, pero se implementan para admitir el uso de foreach
( For Each
en Visual Basic) para recorrer en iteración la colección.In this example, members of these interfaces are not explicitly called, but they are implemented to support the use of foreach
(For Each
in Visual Basic) to iterate through the collection. Este ejemplo es una aplicación de consola completa.This example is a complete Console app. Para compilar la aplicación Visual Basic, cambie el objeto startup a Sub Main en la página de propiedades del proyecto.To compile the Visual Basic app, change the Startup object to Sub Main in the project's Properties page.
Para obtener un ejemplo que muestra cómo implementar la IEnumerable interfaz, vea implementar la interfaz IEnumerable en una clase de colección .For a sample that shows how to implement the IEnumerable interface, see Implementing the IEnumerable Interface in a Collection Class
using System;
using System.Collections;
// Simple business object.
public class Person
{
public Person(string fName, string lName)
{
this.firstName = fName;
this.lastName = lName;
}
public string firstName;
public string lastName;
}
// Collection of Person objects. This class
// implements IEnumerable so that it can be used
// with ForEach syntax.
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];
}
}
// Implementation for the GetEnumerator method.
IEnumerator IEnumerable.GetEnumerator()
{
return (IEnumerator) GetEnumerator();
}
public PeopleEnum GetEnumerator()
{
return new PeopleEnum(_people);
}
}
// When you implement IEnumerable, you must also implement IEnumerator.
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;
}
object IEnumerator.Current
{
get
{
return Current;
}
}
public Person 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
*
*/
Imports System.Collections
' Simple business object.
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
' Collection of Person objects, which implements IEnumerable so that
' it can be used with ForEach syntax.
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
' Implementation of GetEnumerator.
Public Function GetEnumerator() As IEnumerator _
Implements IEnumerable.GetEnumerator
Return New PeopleEnum(_people)
End Function
End Class
' When you implement IEnumerable, you must also implement IEnumerator.
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
Comentarios
IEnumerable es la interfaz base para todas las colecciones no genéricas que se pueden enumerar.IEnumerable is the base interface for all non-generic collections that can be enumerated. Para la versión genérica de esta interfaz, vea System.Collections.Generic.IEnumerable<T> .For the generic version of this interface see System.Collections.Generic.IEnumerable<T>. IEnumerable contiene un método único, GetEnumerator , que devuelve un IEnumerator .IEnumerable contains a single method, GetEnumerator, which returns an IEnumerator. IEnumerator proporciona la capacidad de recorrer en iteración la colección mediante la exposición de una Current propiedad y MoveNext Reset métodos y.IEnumerator provides the ability to iterate through the collection by exposing a Current property and MoveNext and Reset methods.
Se recomienda implementar IEnumerable y en las clases de IEnumerator colección para habilitar la foreach
For Each
sintaxis (en Visual Basic), pero IEnumerable no es necesario implementarla.It is a best practice to implement IEnumerable and IEnumerator on your collection classes to enable the foreach
(For Each
in Visual Basic) syntax, however implementing IEnumerable is not required. Si la colección no implementa IEnumerable , debe seguir el patrón de iterador para admitir esta sintaxis proporcionando un GetEnumerator
método que devuelva una interfaz, clase o struct.If your collection does not implement IEnumerable, you must still follow the iterator pattern to support this syntax by providing a GetEnumerator
method that returns an interface, class or struct. Al utilizar Visual Basic, debe proporcionar una IEnumerator implementación, devuelta por GetEnumerator
.When using Visual Basic, you must provide an IEnumerator implementation, which is returned by GetEnumerator
. Al desarrollar con C#, debe proporcionar una clase que contenga una Current
propiedad, MoveNext
Reset
los métodos y, tal y como se describe en IEnumerator , pero la clase no tiene que implementar IEnumerator .When developing with C# you must provide a class that contains a Current
property, and MoveNext
and Reset
methods as described by IEnumerator, but the class does not have to implement IEnumerator.
Métodos
GetEnumerator() |
Devuelve un enumerador que recorre en iteración una colección.Returns an enumerator that iterates through a collection. |
Métodos de extensión
Cast<TResult>(IEnumerable) |
Convierte los elementos de IEnumerable en el tipo especificado.Casts the elements of an IEnumerable to the specified type. |
OfType<TResult>(IEnumerable) |
Filtra los elementos de IEnumerable en función de un tipo especificado.Filters the elements of an IEnumerable based on a specified type. |
AsParallel(IEnumerable) |
Habilita la paralelización de una consulta.Enables parallelization of a query. |
AsQueryable(IEnumerable) |
Convierte una interfaz IEnumerable en IQueryable.Converts an IEnumerable to an IQueryable. |