IEnumerator.Reset IEnumerator.Reset IEnumerator.Reset IEnumerator.Reset Method

定義

列挙子を初期位置、つまりコレクションの最初の要素の前に設定します。Sets the enumerator to its initial position, which is before the first element in the collection.

public:
 void Reset();
public void Reset ();
abstract member Reset : unit -> unit
Public Sub Reset ()

例外

コレクションは、列挙子の作成後に変更されました。The collection was modified after the enumerator was created.

次のコード例の実装を示します、IEnumeratorカスタム コレクション用のインターフェイス。The following code example demonstrates the implementation of the IEnumerator interfaces for a custom collection. この例でReset明示的に呼び出されないの使用をサポートするために実装されますが、 foreach (for each Visual Basic で)。In this example, Reset is not explicitly called, but it is implemented to support the use of foreach (for each in Visual Basic). このコード例の例の一部、IEnumeratorインターフェイス。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

注釈

追加、変更、または、要素の動作を削除するなど、コレクションに変更が加えられた場合Resetが定義されていません。If changes are made to the collection, such as adding, modifying, or deleting elements, the behavior of Reset is undefined.

Resetメソッドが COM 相互運用性を提供します。The Reset method is provided for COM interoperability. 実装する。 必ずしも必要はありません。代わりに、実装者をスローする可能性をNotSupportedExceptionします。It does not necessarily need to be implemented; instead, the implementer can simply throw a NotSupportedException.

注意 (実装者)

すべての呼び出しをReset()列挙子の同じ状態になる必要があります。All calls to Reset() must result in the same state for the enumerator. 推奨される実装では、最初の要素の前に、コレクションの先頭に、列挙子を移動します。The preferred implementation is to move the enumerator to the beginning of the collection, before the first element. 列挙子の作成と一貫した後、コレクションが変更された場合、列挙子を無効にMoveNext()Currentします。This invalidates the enumerator if the collection has been modified since the enumerator was created, which is consistent with MoveNext() and Current.

適用対象

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