IEnumerable Interface


제네릭이 아닌 컬렉션에서 단순하게 반복할 수 있도록 지원하는 열거자를 노출합니다.Exposes an enumerator, which supports a simple iteration over a non-generic collection.

public interface class IEnumerable
public interface IEnumerable
public interface IEnumerable
public interface IEnumerable
type IEnumerable = interface
Public Interface IEnumerable


다음 코드 예제에서는 IEnumerableIEnumerator 인터페이스를 구현 하 여 사용자 지정 컬렉션을 반복 하는 모범 사례를 보여 줍니다.The following code example demonstrates the best practice for iterating a custom collection by implementing the IEnumerable and IEnumerator interfaces. 이 예제에서는 이러한 인터페이스의 멤버를 명시적으로 호출 하지 않지만, foreach (Visual Basic의For Each)를 사용 하 여 컬렉션을 반복할 수 있도록 구현 됩니다.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. 이 예제는 완전 한 콘솔 앱.This example is a complete Console app. Visual Basic 앱을 컴파일하려면 프로젝트의 속성 페이지에서 시작 개체Sub Main 로 변경 합니다.To compile the Visual Basic app, change the Startup object to Sub Main in the project's Properties page.

IEnumerable 인터페이스를 구현 하는 방법을 보여 주는 샘플은 컬렉션 클래스에서 IEnumerable 인터페이스 구현 을 참조 하세요.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()
        return (position < _people.Length);

    public void Reset()
        position = -1;

    object IEnumerator.Current
            return Current;

    public Person Current
                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
                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)

    End Sub
End Class

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


IEnumerable는 열거할 수 있는 제네릭이 아닌 모든 컬렉션에 대 한 기본 인터페이스입니다.IEnumerable is the base interface for all non-generic collections that can be enumerated. 이 인터페이스의 제네릭 버전은 System.Collections.Generic.IEnumerable<T>를 참조 하세요.For the generic version of this interface see System.Collections.Generic.IEnumerable<T>. IEnumerable에는 IEnumerator를 반환 하는 단일 메서드인 GetEnumerator이 포함 되어 있습니다.IEnumerable contains a single method, GetEnumerator, which returns an IEnumerator. IEnumerator Current 속성을 노출 하 고 MoveNextReset 메서드를 표시 하 여 컬렉션을 반복 하는 기능을 제공 합니다.IEnumerator provides the ability to iterate through the collection by exposing a Current property and MoveNext and Reset methods.

컬렉션 클래스에 IEnumerableIEnumerator를 구현 하 여 foreach``For Each (Visual Basic) 구문을 사용 하도록 설정 하는 것이 가장 좋습니다. 그러나 IEnumerable는 구현 하지 않아도 됩니다.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. 컬렉션에서 IEnumerable을 구현 하지 않는 경우에는 인터페이스, 클래스 또는 구조체를 반환 하는 GetEnumerator 메서드를 제공 하 여이 구문을 지원 하기 위해 여전히 반복기 패턴을 따라야 합니다.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. Visual Basic를 사용 하는 경우 GetEnumerator에서 반환 되는 IEnumerator 구현을 제공 해야 합니다.When using Visual Basic, you must provide an IEnumerator implementation, which is returned by GetEnumerator. 를 사용 하 C# 여 개발 하는 경우 Current 속성을 포함 하는 클래스를 제공 해야 하며 IEnumerator에 설명 된 대로 MoveNextReset 메서드를 제공 해야 하지만 클래스는 IEnumerator를 구현할 필요가 없습니다.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.



컬렉션 전체를 반복하는 열거자를 반환합니다.Returns an enumerator that iterates through a collection.

Extension Methods


IEnumerable의 요소를 지정된 형식으로 캐스팅합니다.Casts the elements of an IEnumerable to the specified type.


지정된 형식에 따라 IEnumerable의 요소를 필터링합니다.Filters the elements of an IEnumerable based on a specified type.


쿼리를 병렬화할 수 있도록 합니다.Enables parallelization of a query.


IEnumerableIQueryable로 변환합니다.Converts an IEnumerable to an IQueryable.

Applies to

See also