IEnumerator.MoveNext 메서드

정의

열거자를 컬렉션의 다음 요소로 이동합니다.Advances the enumerator to the next element of the collection.

public:
 bool MoveNext();
public bool MoveNext ();
abstract member MoveNext : unit -> bool
Public Function MoveNext () As Boolean

반환

열거자가 다음 요소로 이동한 경우 true이(가) 반환되고, 컬렉션의 끝을 지난 경우 false이(가) 반환됩니다.true if the enumerator was successfully advanced to the next element; false if the enumerator has passed the end of the collection.

예외

열거자가 만들어진 후에 컬렉션이 수정되었습니다.The collection was modified after the enumerator was created.

예제

다음 코드 예제에서는 구현의 IEnumerator 사용자 지정 컬렉션에 대 한 인터페이스입니다.The following code example demonstrates the implementation of the IEnumerator interfaces for a custom collection. 이 예에서 MoveNext 명시적으로 호출 되지 않습니다 하지만의 사용을 지원 하도록 구현 됩니다 foreach (for each Visual basic에서).In this example, MoveNext is not explicitly called, but it is implemented to support the use of foreach (for each in Visual Basic). 이 코드 예제는에 대 한 보다 큰 예제의 일부는 IEnumerator 인터페이스입니다.This code example is part of a larger example for the IEnumerator interface.

// 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();
            }
        }
    }
}
' 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

설명

열거자를 만든 후 또는 후 합니다 Reset 메서드가 호출 되 면 열거자가 컬렉션 및 첫 번째 호출은 첫 번째 요소 앞에 위치를 MoveNext 메서드는 컬렉션의 첫 번째 요소를 통해 열거자를 이동 합니다.After an enumerator is created or after the Reset method is called, an enumerator is positioned before the first element of the collection, and the first call to the MoveNext method moves the enumerator over the first element of the collection.

경우 MoveNext 열거자를 컬렉션의 끝 컬렉션의 마지막 요소 뒤에 배치 되는 전달 하 고 MoveNext 반환 false합니다.If MoveNext passes the end of the collection, the enumerator is positioned after the last element in the collection and MoveNext returns false. 열거자가 있는 경우이 위치에 대 한 후속 호출은 MoveNext 반환할 수도 false 때까지 Reset 라고 합니다.When the enumerator is at this position, subsequent calls to MoveNext also return false until Reset is called.

추가, 수정 또는 동작 요소를 삭제 하는 등 컬렉션 변경 되 면 MoveNext 정의 되지 않습니다.If changes are made to the collection, such as adding, modifying, or deleting elements, the behavior of MoveNext is undefined.

적용 대상

추가 정보