DictionaryBase.GetEnumerator Méthode

Définition

Retourne IDictionaryEnumerator qui itère au sein de l'instance de DictionaryBase.Returns an IDictionaryEnumerator that iterates through the DictionaryBase instance.

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

Retours

Implémente

Exemples

L’exemple de code suivant implémente la classe DictionaryBase et utilise cette implémentation pour créer un dictionnaire de String clés et de valeurs qui ont un Length de 5 caractères ou moins.The following code example implements the DictionaryBase class and uses that implementation to create a dictionary of String keys and values that have a Length of 5 characters or less.

using namespace System;
using namespace System::Collections;

public ref class ShortStringDictionary: public DictionaryBase
{
public:

   property String^ Item [String^]
   {
      String^ get( String^ key )
      {
         return (dynamic_cast<String^>(Dictionary[ key ]));
      }

      void set( String^ value, String^ key )
      {
         Dictionary[ key ] = value;
      }
   }

   property ICollection^ Keys 
   {
      ICollection^ get()
      {
         return (Dictionary->Keys);
      }
   }

   property ICollection^ Values 
   {
      ICollection^ get()
      {
         return (Dictionary->Values);
      }
   }
   void Add( String^ key, String^ value )
   {
      Dictionary->Add( key, value );
   }

   bool Contains( String^ key )
   {
      return (Dictionary->Contains( key ));
   }

   void Remove( String^ key )
   {
      Dictionary->Remove( key );
   }


protected:
   virtual void OnInsert( Object^ key, Object^ value ) override
   {
      if ( key->GetType() != Type::GetType( "System.String" ) )
            throw gcnew ArgumentException( "key must be of type String.","key" );
      else
      {
         String^ strKey = dynamic_cast<String^>(key);
         if ( strKey->Length > 5 )
                  throw gcnew ArgumentException( "key must be no more than 5 characters in length.","key" );
      }

      if ( value->GetType() != Type::GetType( "System.String" ) )
            throw gcnew ArgumentException( "value must be of type String.","value" );
      else
      {
         String^ strValue = dynamic_cast<String^>(value);
         if ( strValue->Length > 5 )
                  throw gcnew ArgumentException( "value must be no more than 5 characters in length.","value" );
      }
   }

   virtual void OnRemove( Object^ key, Object^ /*value*/ ) override
   {
      if ( key->GetType() != Type::GetType( "System.String" ) )
            throw gcnew ArgumentException( "key must be of type String.","key" );
      else
      {
         String^ strKey = dynamic_cast<String^>(key);
         if ( strKey->Length > 5 )
                  throw gcnew ArgumentException( "key must be no more than 5 characters in length.","key" );
      }
   }

   virtual void OnSet( Object^ key, Object^ /*oldValue*/, Object^ newValue ) override
   {
      if ( key->GetType() != Type::GetType( "System.String" ) )
            throw gcnew ArgumentException( "key must be of type String.","key" );
      else
      {
         String^ strKey = dynamic_cast<String^>(key);
         if ( strKey->Length > 5 )
                  throw gcnew ArgumentException( "key must be no more than 5 characters in length.","key" );
      }

      if ( newValue->GetType() != Type::GetType( "System.String" ) )
            throw gcnew ArgumentException( "newValue must be of type String.","newValue" );
      else
      {
         String^ strValue = dynamic_cast<String^>(newValue);
         if ( strValue->Length > 5 )
                  throw gcnew ArgumentException( "newValue must be no more than 5 characters in length.","newValue" );
      }
   }

   virtual void OnValidate( Object^ key, Object^ value ) override
   {
      if ( key->GetType() != Type::GetType( "System.String" ) )
            throw gcnew ArgumentException( "key must be of type String.","key" );
      else
      {
         String^ strKey = dynamic_cast<String^>(key);
         if ( strKey->Length > 5 )
                  throw gcnew ArgumentException( "key must be no more than 5 characters in length.","key" );
      }

      if ( value->GetType() != Type::GetType( "System.String" ) )
            throw gcnew ArgumentException( "value must be of type String.","value" );
      else
      {
         String^ strValue = dynamic_cast<String^>(value);
         if ( strValue->Length > 5 )
                  throw gcnew ArgumentException( "value must be no more than 5 characters in length.","value" );
      }
   }

};

void PrintKeysAndValues2( ShortStringDictionary^ myCol );
void PrintKeysAndValues3( ShortStringDictionary^ myCol );
int main()
{
   // Creates and initializes a new DictionaryBase.
   ShortStringDictionary^ mySSC = gcnew ShortStringDictionary;

   // Adds elements to the collection.
   mySSC->Add( "One", "a" );
   mySSC->Add( "Two", "ab" );
   mySSC->Add( "Three", "abc" );
   mySSC->Add( "Four", "abcd" );
   mySSC->Add( "Five", "abcde" );

   // Display the contents of the collection using the enumerator.
   Console::WriteLine( "Contents of the collection (using enumerator):" );
   PrintKeysAndValues2( mySSC );

   // Display the contents of the collection using the Keys property and the Item property.
   Console::WriteLine( "Initial contents of the collection (using Keys and Item):" );
   PrintKeysAndValues3( mySSC );

   // Tries to add a value that is too long.
   try
   {
      mySSC->Add( "Ten", "abcdefghij" );
   }
   catch ( ArgumentException^ e ) 
   {
      Console::WriteLine( e );
   }

   // Tries to add a key that is too long.
   try
   {
      mySSC->Add( "Eleven", "ijk" );
   }
   catch ( ArgumentException^ e ) 
   {
      Console::WriteLine( e );
   }

   Console::WriteLine();

   // Searches the collection with Contains.
   Console::WriteLine( "Contains \"Three\": {0}", mySSC->Contains( "Three" ) );
   Console::WriteLine( "Contains \"Twelve\": {0}", mySSC->Contains( "Twelve" ) );
   Console::WriteLine();

   // Removes an element from the collection.
   mySSC->Remove( "Two" );

   // Displays the contents of the collection.
   Console::WriteLine( "After removing \"Two\":" );
   PrintKeysAndValues2( mySSC );
}

// Uses the enumerator. 
void PrintKeysAndValues2( ShortStringDictionary^ myCol )
{
   DictionaryEntry myDE;
   System::Collections::IEnumerator^ myEnumerator = myCol->GetEnumerator();
   while ( myEnumerator->MoveNext() )
      if ( myEnumerator->Current != nullptr )
   {
      myDE =  *dynamic_cast<DictionaryEntry^>(myEnumerator->Current);
      Console::WriteLine( "   {0,-5} : {1}", myDE.Key, myDE.Value );
   }

   Console::WriteLine();
}


// Uses the Keys property and the Item property.
void PrintKeysAndValues3( ShortStringDictionary^ myCol )
{
   ICollection^ myKeys = myCol->Keys;
   IEnumerator^ myEnum1 = myKeys->GetEnumerator();
   while ( myEnum1->MoveNext() )
   {
      String^ k = safe_cast<String^>(myEnum1->Current);
      Console::WriteLine( "   {0,-5} : {1}", k, myCol->Item[ k ] );
   }

   Console::WriteLine();
}

/* 
This code produces the following output.

Contents of the collection (using enumerator):
   Three : abc
   Five  : abcde
   Two   : ab
   One   : a
   Four  : abcd

Initial contents of the collection (using Keys and Item):
   Three : abc
   Five  : abcde
   Two   : ab
   One   : a
   Four  : abcd

System.ArgumentException: value must be no more than 5 characters in length.
Parameter name: value
   at ShortStringDictionary.OnValidate(Object key, Object value)
   at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
   at SamplesDictionaryBase.Main()
System.ArgumentException: key must be no more than 5 characters in length.
Parameter name: key
   at ShortStringDictionary.OnValidate(Object key, Object value)
   at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
   at SamplesDictionaryBase.Main()

Contains "Three": True
Contains "Twelve": False

After removing "Two":
   Three : abc
   Five  : abcde
   One   : a
   Four  : abcd

*/
using System;
using System.Collections;

public class ShortStringDictionary : DictionaryBase  {

   public String this[ String key ]  {
      get  {
         return( (String) Dictionary[key] );
      }
      set  {
         Dictionary[key] = value;
      }
   }

   public ICollection Keys  {
      get  {
         return( Dictionary.Keys );
      }
   }

   public ICollection Values  {
      get  {
         return( Dictionary.Values );
      }
   }

   public void Add( String key, String value )  {
      Dictionary.Add( key, value );
   }

   public bool Contains( String key )  {
      return( Dictionary.Contains( key ) );
   }

   public void Remove( String key )  {
      Dictionary.Remove( key );
   }

   protected override void OnInsert( Object key, Object value )  {
      if ( key.GetType() != typeof(System.String) )
        {
            throw new ArgumentException( "key must be of type String.", "key" );
        }
        else  {
         String strKey = (String) key;
         if ( strKey.Length > 5 )
            throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );
      }

      if ( value.GetType() != typeof(System.String) )
        {
            throw new ArgumentException( "value must be of type String.", "value" );
        }
        else  {
         String strValue = (String) value;
         if ( strValue.Length > 5 )
            throw new ArgumentException( "value must be no more than 5 characters in length.", "value" );
      }
   }

   protected override void OnRemove( Object key, Object value )  {
      if ( key.GetType() != typeof(System.String) )
        {
            throw new ArgumentException( "key must be of type String.", "key" );
        }
        else  {
         String strKey = (String) key;
         if ( strKey.Length > 5 )
            throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );
      }
   }

   protected override void OnSet( Object key, Object oldValue, Object newValue )  {
      if ( key.GetType() != typeof(System.String) )
        {
            throw new ArgumentException( "key must be of type String.", "key" );
        }
        else  {
         String strKey = (String) key;
         if ( strKey.Length > 5 )
            throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );
      }

      if ( newValue.GetType() != typeof(System.String) )
        {
            throw new ArgumentException( "newValue must be of type String.", "newValue" );
        }
        else  {
         String strValue = (String) newValue;
         if ( strValue.Length > 5 )
            throw new ArgumentException( "newValue must be no more than 5 characters in length.", "newValue" );
      }
   }

   protected override void OnValidate( Object key, Object value )  {
      if ( key.GetType() != typeof(System.String) )
        {
            throw new ArgumentException( "key must be of type String.", "key" );
        }
        else  {
         String strKey = (String) key;
         if ( strKey.Length > 5 )
            throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );
      }

      if ( value.GetType() != typeof(System.String) )
        {
            throw new ArgumentException( "value must be of type String.", "value" );
        }
        else  {
         String strValue = (String) value;
         if ( strValue.Length > 5 )
            throw new ArgumentException( "value must be no more than 5 characters in length.", "value" );
      }
   }

}

public class SamplesDictionaryBase  {

   public static void Main()  {
 
      // Creates and initializes a new DictionaryBase.
      ShortStringDictionary mySSC = new ShortStringDictionary();

      // Adds elements to the collection.
      mySSC.Add( "One", "a" );
      mySSC.Add( "Two", "ab" );
      mySSC.Add( "Three", "abc" );
      mySSC.Add( "Four", "abcd" );
      mySSC.Add( "Five", "abcde" );

      // Display the contents of the collection using foreach. This is the preferred method.
      Console.WriteLine( "Contents of the collection (using foreach):" );
      PrintKeysAndValues1( mySSC );

      // Display the contents of the collection using the enumerator.
      Console.WriteLine( "Contents of the collection (using enumerator):" );
      PrintKeysAndValues2( mySSC );

      // Display the contents of the collection using the Keys property and the Item property.
      Console.WriteLine( "Initial contents of the collection (using Keys and Item):" );
      PrintKeysAndValues3( mySSC );

      // Tries to add a value that is too long.
      try  {
         mySSC.Add( "Ten", "abcdefghij" );
      }
      catch ( ArgumentException e )  {
         Console.WriteLine( e.ToString() );
      }

      // Tries to add a key that is too long.
      try  {
         mySSC.Add( "Eleven", "ijk" );
      }
      catch ( ArgumentException e )  {
         Console.WriteLine( e.ToString() );
      }

      Console.WriteLine();

      // Searches the collection with Contains.
      Console.WriteLine( "Contains \"Three\": {0}", mySSC.Contains( "Three" ) );
      Console.WriteLine( "Contains \"Twelve\": {0}", mySSC.Contains( "Twelve" ) );
      Console.WriteLine();

      // Removes an element from the collection.
      mySSC.Remove( "Two" );

      // Displays the contents of the collection.
      Console.WriteLine( "After removing \"Two\":" );
      PrintKeysAndValues1( mySSC );

   }

   // Uses the foreach statement which hides the complexity of the enumerator.
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintKeysAndValues1( ShortStringDictionary myCol )  {
      foreach ( DictionaryEntry myDE in myCol )
         Console.WriteLine( "   {0,-5} : {1}", myDE.Key, myDE.Value );
      Console.WriteLine();
   }

   // Uses the enumerator. 
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintKeysAndValues2( ShortStringDictionary myCol )  {
      DictionaryEntry myDE;
      System.Collections.IEnumerator myEnumerator = myCol.GetEnumerator();
      while ( myEnumerator.MoveNext() )
         if ( myEnumerator.Current != null )  {
            myDE = (DictionaryEntry) myEnumerator.Current;
            Console.WriteLine( "   {0,-5} : {1}", myDE.Key, myDE.Value );
         }
      Console.WriteLine();
   }

   // Uses the Keys property and the Item property.
   public static void PrintKeysAndValues3( ShortStringDictionary myCol )  {
      ICollection myKeys = myCol.Keys;
      foreach ( String k in myKeys )
         Console.WriteLine( "   {0,-5} : {1}", k, myCol[k] );
      Console.WriteLine();
   }

}


/* 
This code produces the following output.

Contents of the collection (using foreach):
   Three : abc
   Five  : abcde
   Two   : ab
   One   : a
   Four  : abcd

Contents of the collection (using enumerator):
   Three : abc
   Five  : abcde
   Two   : ab
   One   : a
   Four  : abcd

Initial contents of the collection (using Keys and Item):
   Three : abc
   Five  : abcde
   Two   : ab
   One   : a
   Four  : abcd

System.ArgumentException: value must be no more than 5 characters in length.
Parameter name: value
   at ShortStringDictionary.OnValidate(Object key, Object value)
   at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
   at SamplesDictionaryBase.Main()
System.ArgumentException: key must be no more than 5 characters in length.
Parameter name: key
   at ShortStringDictionary.OnValidate(Object key, Object value)
   at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
   at SamplesDictionaryBase.Main()

Contains "Three": True
Contains "Twelve": False

After removing "Two":
   Three : abc
   Five  : abcde
   One   : a
   Four  : abcd

*/

Imports System.Collections

Public Class ShortStringDictionary
   Inherits DictionaryBase

   Default Public Property Item(key As String) As String
      Get
         Return CType(Dictionary(key), String)
      End Get
      Set
         Dictionary(key) = value
      End Set
   End Property

   Public ReadOnly Property Keys() As ICollection
      Get
         Return Dictionary.Keys
      End Get
   End Property

   Public ReadOnly Property Values() As ICollection
      Get
         Return Dictionary.Values
      End Get
   End Property

   Public Sub Add(key As String, value As String)
      Dictionary.Add(key, value)
   End Sub

   Public Function Contains(key As String) As Boolean
      Return Dictionary.Contains(key)
   End Function 'Contains

   Public Sub Remove(key As String)
      Dictionary.Remove(key)
   End Sub

   Protected Overrides Sub OnInsert(key As Object, value As Object)
      If Not GetType(System.String).IsAssignableFrom(key.GetType()) Then
         Throw New ArgumentException("key must be of type String.", "key")
      Else
         Dim strKey As String = CType(key, String)
         If strKey.Length > 5 Then
            Throw New ArgumentException("key must be no more than 5 characters in length.", "key")
         End If
      End If 
      If Not GetType(System.String).IsAssignableFrom(value.GetType()) Then
         Throw New ArgumentException("value must be of type String.", "value")
      Else
         Dim strValue As String = CType(value, String)
         If strValue.Length > 5 Then
            Throw New ArgumentException("value must be no more than 5 characters in length.", "value")
         End If
      End If
   End Sub

   Protected Overrides Sub OnRemove(key As Object, value As Object)
      If Not GetType(System.String).IsAssignableFrom(key.GetType()) Then
         Throw New ArgumentException("key must be of type String.", "key")
      Else
         Dim strKey As String = CType(key, String)
         If strKey.Length > 5 Then
            Throw New ArgumentException("key must be no more than 5 characters in length.", "key")
         End If
      End If
   End Sub

   Protected Overrides Sub OnSet(key As Object, oldValue As Object, newValue As Object)
      If Not GetType(System.String).IsAssignableFrom(key.GetType()) Then
         Throw New ArgumentException("key must be of type String.", "key")
      Else
         Dim strKey As String = CType(key, String)
         If strKey.Length > 5 Then
            Throw New ArgumentException("key must be no more than 5 characters in length.", "key")
         End If
      End If 
      If Not GetType(System.String).IsAssignableFrom(newValue.GetType()) Then
         Throw New ArgumentException("newValue must be of type String.", "newValue")
      Else
         Dim strValue As String = CType(newValue, String)
         If strValue.Length > 5 Then
            Throw New ArgumentException("newValue must be no more than 5 characters in length.", "newValue")
         End If
      End If
   End Sub

   Protected Overrides Sub OnValidate(key As Object, value As Object)
      If Not GetType(System.String).IsAssignableFrom(key.GetType()) Then
         Throw New ArgumentException("key must be of type String.", "key")
      Else
         Dim strKey As String = CType(key, String)
         If strKey.Length > 5 Then
            Throw New ArgumentException("key must be no more than 5 characters in length.", "key")
         End If
      End If 
      If Not GetType(System.String).IsAssignableFrom(value.GetType()) Then
         Throw New ArgumentException("value must be of type String.", "value")
      Else
         Dim strValue As String = CType(value, String)
         If strValue.Length > 5 Then
            Throw New ArgumentException("value must be no more than 5 characters in length.", "value")
         End If
      End If
   End Sub

End Class


Public Class SamplesDictionaryBase

   Public Shared Sub Main()

      ' Creates and initializes a new DictionaryBase.
      Dim mySSC As New ShortStringDictionary()

      ' Adds elements to the collection.
      mySSC.Add("One", "a")
      mySSC.Add("Two", "ab")
      mySSC.Add("Three", "abc")
      mySSC.Add("Four", "abcd")
      mySSC.Add("Five", "abcde")

      ' Display the contents of the collection using For Each. This is the preferred method.
      Console.WriteLine("Contents of the collection (using For Each):")
      PrintKeysAndValues1(mySSC)

      ' Display the contents of the collection using the enumerator.
      Console.WriteLine("Contents of the collection (using enumerator):")
      PrintKeysAndValues2(mySSC)

      ' Display the contents of the collection using the Keys property and the Item property.
      Console.WriteLine("Initial contents of the collection (using Keys and Item):")
      PrintKeysAndValues3(mySSC)

      ' Tries to add a value that is too long.
      Try
          mySSC.Add("Ten", "abcdefghij")
      Catch e As ArgumentException
          Console.WriteLine(e.ToString())
      End Try

      ' Tries to add a key that is too long.
      Try
          mySSC.Add("Eleven", "ijk")
      Catch e As ArgumentException
          Console.WriteLine(e.ToString())
      End Try

      Console.WriteLine()

      ' Searches the collection with Contains.
      Console.WriteLine("Contains ""Three"": {0}", mySSC.Contains("Three"))
      Console.WriteLine("Contains ""Twelve"": {0}", mySSC.Contains("Twelve"))
      Console.WriteLine()

      ' Removes an element from the collection.
      mySSC.Remove("Two")

      ' Displays the contents of the collection.
      Console.WriteLine("After removing ""Two"":")
      PrintKeysAndValues1(mySSC)

    End Sub


    ' Uses the For Each statement which hides the complexity of the enumerator.
    ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
    Public Shared Sub PrintKeysAndValues1(myCol As ShortStringDictionary)
      Dim myDE As DictionaryEntry
      For Each myDE In  myCol
          Console.WriteLine("   {0,-5} : {1}", myDE.Key, myDE.Value)
      Next myDE
      Console.WriteLine()
    End Sub


    ' Uses the enumerator. 
    ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
    Public Shared Sub PrintKeysAndValues2(myCol As ShortStringDictionary)
      Dim myDE As DictionaryEntry
      Dim myEnumerator As System.Collections.IEnumerator = myCol.GetEnumerator()
      While myEnumerator.MoveNext()
          If Not (myEnumerator.Current Is Nothing) Then
            myDE = CType(myEnumerator.Current, DictionaryEntry)
            Console.WriteLine("   {0,-5} : {1}", myDE.Key, myDE.Value)
          End If
      End While
      Console.WriteLine()
    End Sub


    ' Uses the Keys property and the Item property.
    Public Shared Sub PrintKeysAndValues3(myCol As ShortStringDictionary)
      Dim myKeys As ICollection = myCol.Keys
      Dim k As String
      For Each k In  myKeys
          Console.WriteLine("   {0,-5} : {1}", k, myCol(k))
      Next k
      Console.WriteLine()
    End Sub

End Class


'This code produces the following output.
'
'Contents of the collection (using For Each):
'   Three : abc
'   Five  : abcde
'   Two   : ab
'   One   : a
'   Four  : abcd
'
'Contents of the collection (using enumerator):
'   Three : abc
'   Five  : abcde
'   Two   : ab
'   One   : a
'   Four  : abcd
'
'Initial contents of the collection (using Keys and Item):
'   Three : abc
'   Five  : abcde
'   Two   : ab
'   One   : a
'   Four  : abcd
'
'System.ArgumentException: value must be no more than 5 characters in length.
'Parameter name: value
'   at ShortStringDictionary.OnValidate(Object key, Object value)
'   at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
'   at SamplesDictionaryBase.Main()
'System.ArgumentException: key must be no more than 5 characters in length.
'Parameter name: key
'   at ShortStringDictionary.OnValidate(Object key, Object value)
'   at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
'   at SamplesDictionaryBase.Main()
'
'Contains "Three": True
'Contains "Twelve": False
'
'After removing "Two":
'   Three : abc
'   Five  : abcde
'   One   : a
'   Four  : abcd

Remarques

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. Il est donc recommandé d'utiliser foreach plutôt que de manipuler l'énumérateur directement.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, Current n'est pas défini.At this position, Current 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 suivants à MoveNext retournent également false.When the enumerator is at this position, subsequent calls to MoveNext also return false. Si le dernier appel à MoveNext retourné false, Current n’est pas 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 reste valide aussi longtemps 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.

Cette méthode est une opération de O(1).This method is an O(1) operation.

S’applique à

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