MulticastDelegate Classe

Définition

Représente un délégué multicast, c'est-à-dire un délégué dont la liste d'appel peut comporter plusieurs éléments.Represents a multicast delegate; that is, a delegate that can have more than one element in its invocation list.

public ref class MulticastDelegate abstract : Delegate
[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public abstract class MulticastDelegate : Delegate
type MulticastDelegate = class
    inherit Delegate
Public MustInherit Class MulticastDelegate
Inherits Delegate
Héritage
MulticastDelegate
Attributs

Exemples

L’exemple suivant définit une classe, StringContainer, qui comprend une collection de chaînes.The following example defines a class, StringContainer, which includes a collection of strings. L’un de ses membres est CheckAndDisplayDelegate le délégué, qui est utilisé pour afficher les chaînes stockées StringContainer dans un objet qui répondent à des critères particuliers.One of its members is the CheckAndDisplayDelegate delegate, which is used to display strings stored in a StringContainer object that satisfy particular criteria. Le délégué prend une chaîne unique en tant que paramètre et void retourne (ou, dans Visual Basic, il s' Sub agit d’une procédure).The delegate takes a single string as a parameter and returns void (or, in Visual Basic, it's a Sub procedure). Il inclut également une méthode, DisplayAllQualified, qui a un seul paramètre, un CheckAndDisplayDelegate délégué.It also includes a method, DisplayAllQualified, that has a single parameter, a CheckAndDisplayDelegate delegate. Cela permet d’appeler la méthode et d’afficher un ensemble de chaînes filtrées en fonction des méthodes contenues dans le délégué.This allows the method to be called and to display a set of strings that are filtered based on the methods that the delegate contains.

L’exemple définit également une classe utilitaire, StringExtensions, qui a deux méthodes:The example also defines a utility class, StringExtensions, that has two methods:

  • ConStart, qui affiche les chaînes qui commencent par une consonne.ConStart, which displays strings that begin with a consonant.

  • VowelStart, qui affiche les chaînes qui commencent par une voyelle.VowelStart, which displays strings that begin with a vowel.

Notez que les deux méthodes incluent un seul paramètre de chaîne voidet retournent.Note that both methods include a single string parameter and return void. En d’autres termes, les deux méthodes peuvent être assignées au CheckAndDisplayDelegate délégué.In other words, both methods can be assigned to the CheckAndDisplayDelegate delegate.

La Test.Main méthode est le point d’entrée de l’application.The Test.Main method is the application entry point. Il instancie un StringContainer objet, le remplit avec des chaînes et crée deux CheckAndDisplayDelegate délégués, conStart et vowelStart, qui appellent une méthode unique.It instantiates a StringContainer object, populates it with strings, and creates two CheckAndDisplayDelegate delegates, conStart and vowelStart, that invoke a single method. Il appelle ensuite la Delegate.Combine méthode pour créer le multipleDelegates délégué, qui contient initialement les ConStart délégués VowelStart et.It then calls the Delegate.Combine method to create the multipleDelegates delegate, which initially contains the ConStart and VowelStart delegates. Notez que lorsque le multipleDelegates délégué est appelé, il affiche toutes les chaînes dans la collection dans leur ordre d’origine.Note that when the multipleDelegates delegate is invoked, it displays all the strings in the collection in their original order. Cela est dû au fait que chaque lettre est passée séparément à chaque délégué, et que chaque lettre répond aux critères de filtrage d’un seul des deux délégués.This is because each letter is passed separately to each delegate, and each letter meets the filtering criteria of only one of the two delegates. Enfin, après les appels Delegate.Remove à Delegate.Combineet multipleDelegates , contient conStart deux délégués.Finally, after calls to Delegate.Remove and Delegate.Combine, multipleDelegates contains two conStart delegates. Lorsqu’elle est appelée, chaque chaîne de l' StringContainer objet s’affiche deux fois.When it is invoked, each string in the StringContainer object is displayed twice.

using namespace System;
using namespace System::Collections::Generic;

ref class StringContainer
{
private:
   // A generic list object that holds the strings.
   List<String^>^ container = gcnew List<String^>;

public:
   // Define a delegate to handle string display.
   delegate void CheckAndDisplayDelegate(String^ str);

   // A method that adds more strings to the collection.
   void AddString(String^ str)
   {
      container->Add(str);
   }

   // Iterate through the strings and invoke the method(s) that the delegate points to.
   void DisplayAllQualified(CheckAndDisplayDelegate^ displayDelegate)
   {
      for each (String^ str in container)
         displayDelegate(str);
//       System::Collections::IEnumerator^ myEnum = container->GetEnumerator();
//       while ( myEnum->MoveNext() )
//       {
//          String^ str = safe_cast<String^>(myEnum->Current);
//          displayDelegate(str);
//      }
   }
};

//end of class StringContainer
// This class contains a few sample methods
ref class StringFuncs
{
public:

   // This method prints a String* that it is passed if the String* starts with a vowel
   static void ConStart(String^ str)
   {
      if (  !(str[ 0 ] == 'a' || str[ 0 ] == 'e' || str[ 0 ] == 'i' || str[ 0 ] == 'o' || str[ 0 ] == 'u') )
            Console::WriteLine( str );
   }

   // This method prints a String* that it is passed if the String* starts with a consonant
   static void VowelStart( String^ str )
   {
      if ( (str[ 0 ] == 'a' || str[ 0 ] == 'e' || str[ 0 ] == 'i' || str[ 0 ] == 'o' || str[ 0 ] == 'u') )
            Console::WriteLine( str );
   }
};

// This function demonstrates using Delegates, including using the Remove and
// Combine methods to create and modify delegate combinations.
int main()
{
   // Declare the StringContainer class and add some strings
   StringContainer^ container = gcnew StringContainer;
   container->AddString( "This" );
   container->AddString( "is" );
   container->AddString( "a" );
   container->AddString( "multicast" );
   container->AddString( "delegate" );
   container->AddString( "example" );

// RETURN HERE.
   // Create two delegates individually using different methods
   StringContainer::CheckAndDisplayDelegate^ conStart = gcnew StringContainer::CheckAndDisplayDelegate( StringFuncs::ConStart );
   StringContainer::CheckAndDisplayDelegate^ vowelStart = gcnew StringContainer::CheckAndDisplayDelegate( StringFuncs::VowelStart );

   // Get the list of all delegates assigned to this MulticastDelegate instance. 
   array<Delegate^>^ delegateList = conStart->GetInvocationList();
   Console::WriteLine("conStart contains {0} delegate(s).", delegateList->Length);
   delegateList = vowelStart->GetInvocationList();
   Console::WriteLine("vowelStart contains {0} delegate(s).\n", delegateList->Length );

   // Determine whether the delegates are System::Multicast delegates
   if ( dynamic_cast<System::MulticastDelegate^>(conStart) && dynamic_cast<System::MulticastDelegate^>(vowelStart) )
   {
      Console::WriteLine("conStart and vowelStart are derived from MulticastDelegate.\n");
   }

   // Execute the two delegates.
   Console::WriteLine("Executing the conStart delegate:" );
   container->DisplayAllQualified(conStart);
   Console::WriteLine();
   Console::WriteLine("Executing the vowelStart delegate:" );
   container->DisplayAllQualified(vowelStart);

   // Create a new MulticastDelegate and call Combine to add two delegates.
   StringContainer::CheckAndDisplayDelegate^ multipleDelegates =
           dynamic_cast<StringContainer::CheckAndDisplayDelegate^>(Delegate::Combine(conStart, vowelStart));

   // How many delegates does multipleDelegates contain?
   delegateList = multipleDelegates->GetInvocationList();
   Console::WriteLine("\nmultipleDelegates contains {0} delegates.\n", 
                      delegateList->Length );

   //       // Pass this multicast delegate to DisplayAllQualified.
   Console::WriteLine("Executing the multipleDelegate delegate.");
   container->DisplayAllQualified(multipleDelegates);
   // Call remove and combine to change the contained delegates.
   multipleDelegates = dynamic_cast<StringContainer::CheckAndDisplayDelegate^>
                      (Delegate::Remove(multipleDelegates, vowelStart));
   multipleDelegates = dynamic_cast<StringContainer::CheckAndDisplayDelegate^>
                      (Delegate::Combine(multipleDelegates, conStart));

   // Pass multipleDelegates to DisplayAllQualified again.
   Console::WriteLine("\nExecuting the multipleDelegate delegate with two conStart delegates:");
   container->DisplayAllQualified(multipleDelegates);
} 
// The example displays the following output:
//    conStart contains 1 delegate(s).
//    vowelStart contains 1 delegate(s).
//    
//    conStart and vowelStart are derived from MulticastDelegate.
//    
//    Executing the conStart delegate:
//    This
//    multicast
//    delegate
//    
//    Executing the vowelStart delegate:
//    is
//    a
//    example
//    
//    
//    multipleDelegates contains 2 delegates.
//    
//    Executing the multipleDelegate delegate.
//    This
//    is
//    a
//    multicast
//    delegate
//    example
//    
//    Executing the multipleDelegate delegate with two conStart delegates:
//    This
//    This
//    multicast
//    multicast
//    delegate
//    delegate
using System;
using System.Collections.Generic;

class StringContainer
{
   // Define a delegate to handle string display. 
   public delegate void CheckAndDisplayDelegate(string str);

   // A generic list object that holds the strings. 
   private List<String> container = new List<String>();

   // A method that adds strings to the collection. 
   public void AddString(string str) 
   {
      container.Add(str);
   }

   // Iterate through the strings and invoke the method(s) that the delegate points to. 
   public void DisplayAllQualified(CheckAndDisplayDelegate displayDelegate) 
   {
      foreach (var str in container) {
         displayDelegate(str);
      }
   }
 }    

// This class defines some methods to display strings. 
class StringExtensions
{
   // Display a string if it starts with a consonant. 
   public static void ConStart(string str) 
   {
      if (!(str[0]=='a'||str[0]=='e'||str[0]=='i'||str[0]=='o'||str[0]=='u'))
          Console.WriteLine(str);
   }

   // Display a string if it starts with a vowel.
   public static void VowelStart(string str) 
   {
      if ((str[0]=='a'||str[0]=='e'||str[0]=='i'||str[0]=='o'||str[0]=='u'))
          Console.WriteLine(str);
   }
}

// Demonstrate the use of delegates, including the Remove and 
// Combine methods to create and modify delegate combinations. 
class Test
{
   static public void Main()
   {
      // Declare the StringContainer class and add some strings
      StringContainer container = new StringContainer();
      container.AddString("This");
      container.AddString("is");
      container.AddString("a");
      container.AddString("multicast");
      container.AddString("delegate");
      container.AddString("example");

      // Create two delegates individually using different methods.
      StringContainer.CheckAndDisplayDelegate conStart = StringExtensions.ConStart;
      StringContainer.CheckAndDisplayDelegate vowelStart = StringExtensions.VowelStart;

      // Get the list of all delegates assigned to this MulticastDelegate instance. 
      Delegate[] delegateList = conStart.GetInvocationList();
      Console.WriteLine("conStart contains {0} delegate(s).", delegateList.Length);
      delegateList = vowelStart.GetInvocationList();
      Console.WriteLine("vowelStart contains {0} delegate(s).\n", delegateList.Length);

      // Determine whether the delegates are System.Multicast delegates. 
      if (conStart is System.MulticastDelegate && vowelStart is System.MulticastDelegate) 
          Console.WriteLine("conStart and vowelStart are derived from MulticastDelegate.\n");

      // Execute the two delegates.
      Console.WriteLine("Executing the conStart delegate:");
      container.DisplayAllQualified(conStart);
      Console.WriteLine();
      Console.WriteLine("Executing the vowelStart delegate:");
      container.DisplayAllQualified(vowelStart);
      Console.WriteLine();
      
      // Create a new MulticastDelegate and call Combine to add two delegates.
      StringContainer.CheckAndDisplayDelegate multipleDelegates = 
            (StringContainer.CheckAndDisplayDelegate) Delegate.Combine(conStart, vowelStart);

      // How many delegates does multipleDelegates contain?
      delegateList = multipleDelegates.GetInvocationList();
      Console.WriteLine("\nmultipleDelegates contains {0} delegates.\n",
                        delegateList.Length);

      // Pass this multicast delegate to DisplayAllQualified.
      Console.WriteLine("Executing the multipleDelegate delegate.");
      container.DisplayAllQualified(multipleDelegates);

      // Call remove and combine to change the contained delegates.
      multipleDelegates = (StringContainer.CheckAndDisplayDelegate) Delegate.Remove(multipleDelegates, vowelStart);
      multipleDelegates = (StringContainer.CheckAndDisplayDelegate) Delegate.Combine(multipleDelegates, conStart);

      // Pass multipleDelegates to DisplayAllQualified again.
      Console.WriteLine("\nExecuting the multipleDelegate delegate with two conStart delegates:");
      container.DisplayAllQualified(multipleDelegates);
   }
}
// The example displays the following output:
//    conStart contains 1 delegate(s).
//    vowelStart contains 1 delegate(s).
//    
//    conStart and vowelStart are derived from MulticastDelegate.
//    
//    Executing the conStart delegate:
//    This
//    multicast
//    delegate
//    
//    Executing the vowelStart delegate:
//    is
//    a
//    example
//    
//    
//    multipleDelegates contains 2 delegates.
//    
//    Executing the multipleDelegate delegate.
//    This
//    is
//    a
//    multicast
//    delegate
//    example
//    
//    Executing the multipleDelegate delegate with two conStart delegates:
//    This
//    This
//    multicast
//    multicast
//    delegate
//    delegate
Imports System.Collections.Generic

Class StringContainer
    ' Define a delegate to handle string display. 
    Delegate Sub CheckAndPrintDelegate(ByVal str As String)

    ' A generic list object that holds the strings.
    Private container As New List(Of String)()

     ' A method that adds strings to the collection. 
     Public Sub AddString(ByVal s As String)
        container.Add(s)
    End Sub

    ' Iterate through the strings and invoke the method(s) that the delegate points to.
    Public Sub DisplayAllQualified(ByVal displayDelegate As CheckAndPrintDelegate)
        For Each s In container
            displayDelegate(s)
        Next
    End Sub
End Class

' This class defines some methods to display strings. 
Class StringExtensions
    ' Display a string if it starts with a consonant. 
    Public Shared Sub ConStart(ByVal str As String)
        If Not (str.Chars(0) = "a"c Or str.Chars(0) = "e"c Or str.Chars(0) = "i"c _ 
                Or str.Chars(0) = "o"c Or str.Chars(0) = "u"c) Then
            Console.WriteLine(str)
        End If
    End Sub 

    ' Display a string if it starts with a vowel.
    Public Shared Sub VowelStart(ByVal str As String)
        If (str.Chars(0) = "a"c Or str.Chars(0) = "e"c Or str.Chars(0) = "i"c _
            Or str.Chars(0) = "o"c Or str.Chars(0) = "u"c) Then
            Console.WriteLine(str)
        End If
    End Sub 
End Class 

' Demonstrate the use of delegates, including the Remove and 
' Combine methods to create and modify delegate combinations. 
Class Test
    Public Shared Sub Main()
        ' Declare the StringContainer class and add some strings
        Dim container As New StringContainer()
        container.AddString("this")
        container.AddString("is")
        container.AddString("a")
        container.AddString("multicast")
        container.AddString("delegate")
        container.AddString("example")

        ' Create two delegates individually using different methods.
        Dim constart As StringContainer.CheckAndPrintDelegate = AddressOf StringExtensions.ConStart
        Dim vowelStart As StringContainer.CheckAndPrintDelegate = AddressOf StringExtensions.VowelStart

        ' Get the list of all delegates assigned to this MulticastDelegate instance. 
        Dim delegateList() As [Delegate] = conStart.GetInvocationList()
        Console.WriteLine("conStart contains {0} delegate(s).", delegateList.Length)
        delegateList = vowelStart.GetInvocationList()
        Console.WriteLine("vowelStart contains {0} delegate(s).", delegateList.Length)
        Console.WriteLine()
        
        ' Determine whether the delegates are System.Multicast delegates
        If TypeOf conStart Is System.MulticastDelegate And TypeOf vowelStart Is System.MulticastDelegate Then
            Console.WriteLine("conStart and vowelStart are derived from MulticastDelegate.")
            Console.WriteLine()
        End If

        ' Run the two single delegates one after the other.
        Console.WriteLine("Executing the conStart delegate:")
        container.DisplayAllQualified(conStart)
        Console.WriteLine("Executing the vowelStart delegate:")
        container.DisplayAllQualified(vowelStart)
        Console.WriteLine()

        ' Create a new MulticastDelegate and call Combine to add two delegates.
        Dim multipleDelegates As StringContainer.CheckAndPrintDelegate = 
                  CType([Delegate].Combine(conStart, vowelStart), 
                  StringContainer.CheckAndPrintDelegate)

        ' How many delegates does multipleDelegates contain?
        delegateList = multipleDelegates.GetInvocationList()
        Console.WriteLine("{1}multipleDelegates contains {0} delegates.{1}",
                          delegateList.Length, vbCrLf)

        ' Pass this mulitcast delegate to DisplayAllQualified.
        Console.WriteLine("Executing the multipleDelegate delegate.")
        container.DisplayAllQualified(multipleDelegates)

        ' Call remove and combine to change the contained delegates.
        multipleDelegates = CType([Delegate].Remove(multipleDelegates, vowelStart), 
                            StringContainer.CheckAndPrintDelegate)
        multipleDelegates = CType([Delegate].Combine(multipleDelegates, conStart), 
                            StringContainer.CheckAndPrintDelegate)

        ' Pass multipleDelegates to DisplayAllQualified again.
        Console.WriteLine()
        Console.WriteLine("Executing the multipleDelegate delegate with two conStart delegates:")
        container.DisplayAllQualified(multipleDelegates)
    End Sub 
End Class 
' The example displays the following output:
'    conStart contains 1 delegate(s).
'    vowelStart contains 1 delegate(s).
'    
'    conStart and vowelStart are derived from MulticastDelegate.
'    
'    Executing the conStart delegate:
'    This
'    multicast
'    delegate
'    
'    Executing the vowelStart delegate:
'    is
'    a
'    example
'    
'    
'    multipleDelegates contains 2 delegates.
'    
'    Executing the multipleDelegate delegate.
'    This
'    is
'    a
'    multicast
'    delegate
'    example
'    
'    Executing the multipleDelegate delegate with two conStart delegates:
'    This
'    This
'    multicast
'    multicast
'    delegate
'    delegate

Remarques

MulticastDelegateest une classe spéciale.MulticastDelegate is a special class. Les compilateurs et d’autres outils peuvent dériver de cette classe, mais vous ne pouvez pas en dériver explicitement.Compilers and other tools can derive from this class, but you cannot derive from it explicitly. Il en va de même pour Delegate la classe.The same is true of the Delegate class.

Outre les méthodes dont héritent MulticastDelegateles types délégués, le Common Language Runtime fournit deux méthodes spéciales: BeginInvoke et EndInvoke.In addition to the methods that delegate types inherit from MulticastDelegate, the common language runtime provides two special methods: BeginInvoke and EndInvoke. Pour plus d’informations sur ces méthodes, consultez appel de méthodes synchrones de façon asynchrone.For more information about these methods, see Calling Synchronous Methods Asynchronously.

Un MulticastDelegate a une liste liée de délégués, appelée liste d’appel, composée d’un ou de plusieurs éléments.A MulticastDelegate has a linked list of delegates, called an invocation list, consisting of one or more elements. Lorsqu’un délégué multicast est appelé, les délégués de la liste d’appel sont appelés de façon synchrone dans l’ordre dans lequel ils apparaissent.When a multicast delegate is invoked, the delegates in the invocation list are called synchronously in the order in which they appear. Si une erreur se produit pendant l’exécution de la liste, une exception est levée.If an error occurs during execution of the list then an exception is thrown.

Constructeurs

MulticastDelegate(Object, String)

Initialise une nouvelle instance de la classe MulticastDelegate.Initializes a new instance of the MulticastDelegate class.

MulticastDelegate(Type, String)

Initialise une nouvelle instance de la classe MulticastDelegate.Initializes a new instance of the MulticastDelegate class.

Propriétés

Method

Obtient la méthode représentée par le délégué.Gets the method represented by the delegate.

(Hérité de Delegate)
Target

Obtient l'instance de classe sur laquelle le délégué en cours appelle la méthode d'instance.Gets the class instance on which the current delegate invokes the instance method.

(Hérité de Delegate)

Méthodes

Clone()

Crée une copie superficielle du délégué.Creates a shallow copy of the delegate.

(Hérité de Delegate)
CombineImpl(Delegate)

Combine ce Delegate avec le Delegate spécifié pour former un nouveau délégué.Combines this Delegate with the specified Delegate to form a new delegate.

DynamicInvoke(Object[])

Appelle de manière dynamique (à liaison tardive) la méthode représentée par le délégué en cours.Dynamically invokes (late-bound) the method represented by the current delegate.

(Hérité de Delegate)
DynamicInvokeImpl(Object[])

Traite la liste d'appel complète.Processes the full invocation list.

Equals(Object)

Détermine si ce délégué multicast et l'objet spécifié sont égaux.Determines whether this multicast delegate and the specified object are equal.

GetHashCode()

Retourne le code de hachage de cette instance.Returns the hash code for this instance.

GetInvocationList()

Retourne la liste d'appel de ce délégué multicast, dans l'ordre d'appel.Returns the invocation list of this multicast delegate, in invocation order.

GetMethodImpl()

Retourne une méthode statique représentée par MulticastDelegate en cours.Returns a static method represented by the current MulticastDelegate.

GetObjectData(SerializationInfo, StreamingContext)

Remplit un objet SerializationInfo de toutes les données nécessaires pour sérialiser cette instance.Populates a SerializationInfo object with all the data needed to serialize this instance.

GetType()

Obtient le Type de l'instance actuelle.Gets the Type of the current instance.

(Hérité de Object)
MemberwiseClone()

Crée une copie superficielle de l'objet Object actuel.Creates a shallow copy of the current Object.

(Hérité de Object)
RemoveImpl(Delegate)

Enlève un élément dans la liste d'appel de ce MulticastDelegate qui est égal au délégué spécifié.Removes an element from the invocation list of this MulticastDelegate that is equal to the specified delegate.

ToString()

Retourne une chaîne qui représente l'objet actuel.Returns a string that represents the current object.

(Hérité de Object)

Opérateurs

Equality(MulticastDelegate, MulticastDelegate)

Détermine si deux objets MulticastDelegate sont identiques.Determines whether two MulticastDelegate objects are equal.

Inequality(MulticastDelegate, MulticastDelegate)

Détermine si deux objets MulticastDelegate sont inégaux.Determines whether two MulticastDelegate objects are not equal.

Méthodes d’extension

GetMethodInfo(Delegate)

Obtient un objet qui représente la méthode représentée par le délégué spécifié.Gets an object that represents the method represented by the specified delegate.

S’applique à