IOrderedDictionary.GetEnumerator Méthode

Définition

Retourne un énumérateur qui itère au sein de la collection IOrderedDictionary.Returns an enumerator that iterates through the IOrderedDictionary collection.

public:
 System::Collections::IDictionaryEnumerator ^ GetEnumerator();
public System.Collections.IDictionaryEnumerator GetEnumerator ();
abstract member GetEnumerator : unit -> System.Collections.IDictionaryEnumerator
Public Function GetEnumerator () As IDictionaryEnumerator

Retours

IDictionaryEnumerator pour l’intégralité de la collection IOrderedDictionary.An IDictionaryEnumerator for the entire IOrderedDictionary collection.

Implémente

Exemples

L’exemple de code suivant illustre l’implémentation d’un IOrderedDictionary simple basé sur ArrayList la classe.The following code example demonstrates the implementation of a simple IOrderedDictionary based on the ArrayList class. L’implémentation IOrderedDictionary de stocke les noms en tant que clés et noms comme valeurs, avec la spécification ajoutée que chaque prénom est unique.The implemented IOrderedDictionary stores first names as the keys and last names as the values, with the added requirement that each first name is unique. Ce code fait partie d’un exemple de code plus large fourni IOrderedDictionary pour la classe.This code is part of a larger code example provided for the IOrderedDictionary class.

public ref class PeopleEnum : IDictionaryEnumerator
{
private:
    // Enumerators are positioned before the first element
    // until the first MoveNext() call.
    int position;
    ArrayList^ _people;

public:
    PeopleEnum(ArrayList^ list)
    {
        this->Reset();
        _people = list;
    }

    virtual bool MoveNext()
    {
        position++;
        return (position < _people->Count);
    }

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

    virtual property Object^ Current
    {
        Object^ get()
        {
            try
            {
                return _people[position];
            }
            catch (IndexOutOfRangeException^)
            {
                throw gcnew InvalidOperationException();
            }
        }
    }

    virtual property DictionaryEntry Entry
    {
        DictionaryEntry get()
        {
            return (DictionaryEntry)(Current);
        }
    }

    virtual property Object^ Key
    {
        Object^ get()
        {
            try
            {
                return ((DictionaryEntry^)_people[position])->Key;
            }
            catch (IndexOutOfRangeException^)
            {
                throw gcnew InvalidOperationException();
            }
        }
    }

    virtual property Object^ Value
    {
        Object^ get()
        {
            try
            {
                return ((DictionaryEntry^)_people[position])->Value;
            }
            catch (IndexOutOfRangeException^)
            {
                throw gcnew InvalidOperationException();
            }
        }
    }
};

public ref class People : IOrderedDictionary
{
private:
    ArrayList^ _people;

public:
    People(int numItems)
    {
        _people = gcnew ArrayList(numItems);
    }

    int IndexOfKey(Object^ key)
    {
        for (int i = 0; i < _people->Count; i++)
        {
            if (((DictionaryEntry^)_people[i])->Key == key)
                return i;
        }

        // key not found, return -1.
        return -1;
    }

    virtual property Object^ default[Object^]
    {
        Object^ get(Object^ key)
        {
            return ((DictionaryEntry^)_people[IndexOfKey(key)])->Value;
        }
        void set(Object^ key, Object^ value)
        {
            _people[IndexOfKey(key)] = gcnew DictionaryEntry(key, value);
        }
    }

    // IOrderedDictionary Members
    virtual IDictionaryEnumerator^ GetEnumerator()
    {
        return gcnew PeopleEnum(_people);
    }

    virtual void Insert(int index, Object^ key, Object^ value)
    {
        if (IndexOfKey(key) != -1)
        {
            throw gcnew ArgumentException("An element with the same key already exists in the collection.");
        }
        _people->Insert(index, gcnew DictionaryEntry(key, value));
    }

    virtual void RemoveAt(int index)
    {
        _people->RemoveAt(index);
    }

    virtual property Object^ default[int]
    {
        Object^ get(int index)
        {
            return ((DictionaryEntry^)_people[index])->Value;
        }
        void set(int index, Object^ value)
        {
            Object^ key = ((DictionaryEntry^)_people[index])->Key;
            _people[index] = gcnew DictionaryEntry(key, value);
        }
    }

    // IDictionary Members

    virtual void Add(Object^ key, Object^ value)
    {
        if (IndexOfKey(key) != -1)
        {
            throw gcnew ArgumentException("An element with the same key already exists in the collection.");
        }
        _people->Add(gcnew DictionaryEntry(key, value));
    }

    virtual void Clear()
    {
        _people->Clear();
    }

    virtual bool Contains(Object^ key)
    {
        if (IndexOfKey(key) == -1)
        {
            return false;
        }
        else
        {
            return true;
        }
    }

    virtual property bool IsFixedSize
    {
        bool get()
        {
            return false;
        }
    }

    virtual property bool IsReadOnly
    {
        bool get()
        {
            return false;
        }
    }

    virtual property ICollection^ Keys
    {
        ICollection^ get()
        {
            ArrayList^ KeyCollection = gcnew ArrayList(_people->Count);
            for (int i = 0; i < _people->Count; i++)
            {
                KeyCollection->Add( ((DictionaryEntry^)_people[i])->Key );
            }
            return KeyCollection;
        }
    }

    virtual void Remove(Object^ key)
    {
        _people->RemoveAt(IndexOfKey(key));
    }

    virtual property ICollection^ Values
    {
        ICollection ^get()
        {
            ArrayList^ ValueCollection = gcnew ArrayList(_people->Count);
            for (int i = 0; i < _people->Count; i++)
            {
                ValueCollection->Add( ((DictionaryEntry^)_people[i])->Value );
            }
            return ValueCollection;
        }
    }

    // ICollection Members

    virtual void CopyTo(Array^ array, int index)
    {
        _people->CopyTo(array, index);
    }

    virtual property int Count
    {
        int get()
        {
            return _people->Count;
        }
    }

    virtual property bool IsSynchronized
    {
        bool get()
        {
            return _people->IsSynchronized;
        }
    }

    virtual property Object^ SyncRoot
    {
        Object^ get()
        {
            return _people->SyncRoot;
        }
    }

    // IEnumerable Members

    virtual IEnumerator^ IfcGetEnumerator() = IEnumerable::GetEnumerator
    {
        return (IEnumerator^) gcnew PeopleEnum(_people);
    }
};
public class People : IOrderedDictionary
{
    private ArrayList _people;

    public People(int numItems)
    {
        _people = new ArrayList(numItems);
    }

    public int IndexOfKey(object key)
    {
        for (int i = 0; i < _people.Count; i++)
        {
            if (((DictionaryEntry)_people[i]).Key == key)
                return i;
        }

        // key not found, return -1.
        return -1;
    }

    public object this[object key]
    {
        get
        {
            return ((DictionaryEntry)_people[IndexOfKey(key)]).Value;
        }
        set
        {
            _people[IndexOfKey(key)] = new DictionaryEntry(key, value);
        }
    }

    // IOrderedDictionary Members
    public IDictionaryEnumerator GetEnumerator()
    {
        return new PeopleEnum(_people);
    }

    public void Insert(int index, object key, object value)
    {
        if (IndexOfKey(key) != -1)
        {
            throw new ArgumentException("An element with the same key already exists in the collection.");
        }
        _people.Insert(index, new DictionaryEntry(key, value));
    }

    public void RemoveAt(int index)
    {
        _people.RemoveAt(index);
    }

    public object this[int index]
    {
        get
        {
            return ((DictionaryEntry)_people[index]).Value;
        }
        set
        {
            object key = ((DictionaryEntry)_people[index]).Key;
            _people[index] = new DictionaryEntry(key, value);
        }
    }
    // IDictionary Members

    public void Add(object key, object value)
    {
        if (IndexOfKey(key) != -1)
        {
            throw new ArgumentException("An element with the same key already exists in the collection.");
        }
        _people.Add(new DictionaryEntry(key, value));
    }

    public void Clear()
    {
        _people.Clear();
    }

    public bool Contains(object key)
    {
        if (IndexOfKey(key) == -1)
        {
            return false;
        }
        else
        {
            return true;
        }
    }

    public bool IsFixedSize
    {
        get
        {
            return false;
        }
    }

    public bool IsReadOnly
    {
        get
        {
            return false;
        }
    }

    public ICollection Keys
    {
        get
        {
            ArrayList KeyCollection = new ArrayList(_people.Count);
            for (int i = 0; i < _people.Count; i++)
            {
                KeyCollection.Add( ((DictionaryEntry)_people[i]).Key );
            }
            return KeyCollection;
        }
    }

    public void Remove(object key)
    {
        _people.RemoveAt(IndexOfKey(key));
    }

    public ICollection Values
    {
        get
        {
            ArrayList ValueCollection = new ArrayList(_people.Count);
            for (int i = 0; i < _people.Count; i++)
            {
                ValueCollection.Add( ((DictionaryEntry)_people[i]).Value );
            }
            return ValueCollection;
        }
    }


    // ICollection Members

    public void CopyTo(Array array, int index)
    {
        _people.CopyTo(array, index);
    }

    public int Count
    {
        get
        {
            return _people.Count;
        }
    }

    public bool IsSynchronized
    {
        get
        {
            return _people.IsSynchronized;
        }
    }

    public object SyncRoot
    {
        get
        {
            return _people.SyncRoot;
        }
    }

    // IEnumerable Members

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

public class PeopleEnum : IDictionaryEnumerator
{
    public ArrayList _people;
    
    // Enumerators are positioned before the first element
    // until the first MoveNext() call.
    int position = -1;

    public PeopleEnum(ArrayList list)
    {
        _people = list;
    }

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

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

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

    public DictionaryEntry Entry
    {
        get
        {
            return (DictionaryEntry)Current;
        }
    }

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

    public object Value
    {
        get
        {
            try
            {
                return ((DictionaryEntry)_people[position]).Value;
            }
            catch (IndexOutOfRangeException)
            {
                throw new InvalidOperationException();
            }
        }
    }
}
Public Class People
    Implements IOrderedDictionary
    Private _people As ArrayList

    Public Sub New(ByVal numItems As Integer)
        _people = New ArrayList(numItems)
    End Sub

    Public Function IndexOfKey(ByVal key As Object) As Integer
        Dim i As Integer
        For i = 0 To _people.Count - 1
            If CType(_people(i), DictionaryEntry).Key = key Then
                Return i
            End If
        Next i

        ' key not found, return -1.
        Return -1
    End Function

    ' IOrderedDictionary Members
    Public Function GetEnumerator() As IDictionaryEnumerator _
        Implements IOrderedDictionary.GetEnumerator

        Return New PeopleEnum(_people)
    End Function

    Public Sub Insert(ByVal index As Integer, ByVal key As Object, _
        ByVal value As Object) Implements IOrderedDictionary.Insert

        If Not IndexOfKey(key) = -1 Then
            Throw New ArgumentException("An element with the same key already exists in the collection.")
        End If
        _people.Insert(index, New DictionaryEntry(key, value))
    End Sub

    Public Sub RemoveAt(ByVal index As Integer) _
        Implements IOrderedDictionary.RemoveAt

        _people.RemoveAt(index)
    End Sub

    Public Property Item(ByVal index As Integer) As Object _
        Implements IOrderedDictionary.Item

        Get
            Return CType(_people(index), DictionaryEntry).Value
        End Get
        Set(ByVal value As Object)
            Dim key As Object = CType(_people(index), DictionaryEntry).Key
            _people(index) = New DictionaryEntry(key, value)
        End Set
    End Property

    ' IDictionary Members
    Public Function IDictionaryGetEnumerator() As IDictionaryEnumerator _
    Implements IDictionary.GetEnumerator

        Return New PeopleEnum(_people)
    End Function

    Public Property Item(ByVal key As Object) As Object _
        Implements IDictionary.Item

        Get
            Return CType(_people(IndexOfKey(key)), DictionaryEntry).Value
        End Get
        Set(ByVal value)
            _people(IndexOfKey(key)) = New DictionaryEntry(key, value)
        End Set
    End Property


    Public Sub Add(ByVal key As Object, ByVal value As Object) _
        Implements IDictionary.Add

        If Not IndexOfKey(key) = -1 Then
            Throw New ArgumentException("An element with the same key already exists in the collection.")
        End If

        _people.Add(New DictionaryEntry(key, value))
    End Sub

    Public Sub Clear() Implements IDictionary.Clear
        _people.Clear()
    End Sub

    Public Function Contains(ByVal key As Object) As Boolean _
        Implements IDictionary.Contains

        If IndexOfKey(key) = -1 Then
            Return False
        Else
            Return True
        End If
    End Function

    Public ReadOnly Property IsFixedSize() As Boolean _
        Implements IDictionary.IsFixedSize

        Get
            Return False
        End Get
    End Property

    Public ReadOnly Property IsReadOnly() As Boolean _
        Implements IDictionary.IsReadOnly
        Get
            Return False
        End Get
    End Property

    Public ReadOnly Property Keys() As ICollection _
        Implements IDictionary.Keys
        Get
            Dim KeyCollection As ArrayList = New ArrayList(_people.Count)
            Dim i As Integer
            For i = 0 To _people.Count - 1
                KeyCollection.Add( CType(_people(i), DictionaryEntry).Key )
            Next i
            Return KeyCollection
        End Get
    End Property

    Public Sub Remove(ByVal key As Object) _
        Implements IDictionary.Remove

        _people.RemoveAt(IndexOfKey(key))
    End Sub

    Public ReadOnly Property Values() As ICollection _
        Implements IDictionary.Values
        Get
            Dim ValueCollection As ArrayList = New ArrayList(_people.Count)
            Dim i As Integer
            For i = 0 To _people.Count - 1
                ValueCollection.Add( CType(_people(i), DictionaryEntry).Value )
            Next i
            Return ValueCollection
        End Get
    End Property

    ' ICollection Members
    Public Sub CopyTo(ByVal array As Array, ByVal index As Integer) _
    Implements ICollection.CopyTo

        _people.CopyTo(Array, index)
    End Sub

    Public ReadOnly Property Count() As Integer _
        Implements ICollection.Count

        Get
            Return _people.Count
        End Get
    End Property

    Public ReadOnly Property IsSynchronized() As Boolean _
        Implements ICollection.IsSynchronized

        Get
            Return _people.IsSynchronized
        End Get
    End Property

    Public ReadOnly Property SyncRoot() As Object _
        Implements ICollection.SyncRoot

        Get
            Return _people.SyncRoot
        End Get
    End Property

    ' IEnumerable Members
    Public Function IEnumerableGetEnumerator() As IEnumerator _
        Implements IEnumerable.GetEnumerator

        Return New PeopleEnum(_people)
    End Function
End Class

Public Class PeopleEnum
    Implements IDictionaryEnumerator

    Public _people As ArrayList

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

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

    Public Function MoveNext() As Boolean _
        Implements IEnumerator.MoveNext

        position = position + 1
        Return (position < _people.Count)
    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 e As IndexOutOfRangeException
                Throw New InvalidOperationException()
            End Try
        End Get
    End Property

    Public ReadOnly Property Entry() As DictionaryEntry _
        Implements IDictionaryEnumerator.Entry
        Get
            Return CType(Current, DictionaryEntry)
        End Get
    End Property

    Public ReadOnly Property Key() As Object _
        Implements IDictionaryEnumerator.Key

        Get
            Try
                Return CType(_people(position), DictionaryEntry).Key
            Catch e As IndexOutOfRangeException
                Throw New InvalidOperationException()
            End Try
        End Get
    End Property

    Public ReadOnly Property Value() As Object _
        Implements IDictionaryEnumerator.Value

        Get
            Try
                Return CType(_people(position), DictionaryEntry).Value
            Catch e As IndexOutOfRangeException
                Throw New InvalidOperationException()
            End Try
        End Get
    End Property
End Class

Remarques

[Visual Basic, C#][Visual Basic, C#]

L'instruction foreach du langage C# (for each en Visual Basic) se charge de la complexité des énumérateurs.The foreach statement of the C# language (for each in Visual Basic) hides the complexity of the enumerators. Par conséquent, foreach l’utilisation de est recommandée au lieu de manipuler directement l’énumérateur.Therefore, using foreach is recommended instead of directly manipulating the enumerator.

Les énumérateurs peuvent être utilisés pour lire les données de la collection, mais ils ne permettent pas de modifier la collection sous-jacente.Enumerators can be used to read the data in the collection, but they cannot be used to modify the underlying collection.

Au départ, l'énumérateur est positionné avant le premier élément de la collection.Initially, the enumerator is positioned before the first element in the collection. Reset replace également l'énumérateur à cette position.Reset also brings the enumerator back to this position. À cette position, la Current propriété n’est pas définie.At this position, the Current property is undefined. Par conséquent, vous devez appeler MoveNext pour avancer l'énumérateur jusqu'au premier élément de la collection avant de lire la valeur de Current.Therefore, you must call MoveNext to advance the enumerator to the first element of the collection before reading the value of Current.

Current retourne le même objet tant que MoveNext ou Reset n'est pas appelé.Current returns the same object until either MoveNext or Reset is called. MoveNext affecte l'élément suivant à Current.MoveNext sets Current to the next element.

Si MoveNext passe la fin de la collection, l’énumérateur est positionné après le dernier élément de la collection et MoveNext retourne false.If MoveNext passes the end of the collection, the enumerator is positioned after the last element in the collection and MoveNext returns false. Lorsque l’énumérateur se trouve à cette position, les appels MoveNext suivants à falseretournent également.When the enumerator is at this position, subsequent calls to MoveNext also return false. Si le dernier appel à MoveNext Current retourné falseest non défini.If the last call to MoveNext returned false, Current is undefined. Pour attribuer une nouvelle fois Current au premier élément de la collection, vous pouvez appeler Reset suivi de MoveNext.To set Current to the first element of the collection again, you can call Reset followed by MoveNext.

Un énumérateur est valide tant que la collection demeure inchangée.An enumerator remains valid as long as the collection remains unchanged. Si des modifications sont apportées à la collection, telles que l’ajout, la modification ou la suppression d’éléments, l’énumérateur est définitivement invalidé et son comportement n’est pas défini.If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated and its behavior is undefined.

Comme l’énumérateur ne dispose pas d’un accès exclusif à la collection, l’énumération d’une collection n’est pas intrinsèquement une procédure thread-safe.The enumerator does not have exclusive access to the collection; therefore, enumerating through a collection is intrinsically not a thread-safe procedure. Pour garantir la sécurité des threads pendant l'énumération, vous pouvez verrouiller la collection tout au long de cette opération.To guarantee thread safety during enumeration, you can lock the collection during the entire enumeration. Pour permettre à plusieurs threads d’accéder en lecture et en écriture à la collection, vous devez implémenter votre propre synchronisation.To allow the collection to be accessed by multiple threads for reading and writing, you must implement your own synchronization.

S’applique à