MulticastDelegate Klasa

Definicja

Reprezentuje delegata multiemisji; oznacza to, że delegat, który może mieć więcej niż jeden element na liście wywołań.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
Dziedziczenie
MulticastDelegate
Atrybuty

Przykłady

W poniższym przykładzie zdefiniowano klasę StringContainer, która zawiera kolekcję ciągów.The following example defines a class, StringContainer, which includes a collection of strings. Jeden z jego składowych jest delegatem CheckAndDisplayDelegate, który jest używany do wyświetlania ciągów przechowywanych w obiekcie StringContainer, który spełnia określone kryteria.One of its members is the CheckAndDisplayDelegate delegate, which is used to display strings stored in a StringContainer object that satisfy particular criteria. Obiekt delegowany przyjmuje jeden ciąg jako parametr i zwraca void (lub w Visual Basic, jest to Sub procedura).The delegate takes a single string as a parameter and returns void (or, in Visual Basic, it's a Sub procedure). Zawiera również metodę, DisplayAllQualified, która ma jeden parametr, CheckAndDisplayDelegate delegata.It also includes a method, DisplayAllQualified, that has a single parameter, a CheckAndDisplayDelegate delegate. Dzięki temu można wywołać metodę i wyświetlić zestaw ciągów, które są filtrowane na podstawie metod, które zawiera delegat.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.

W przykładzie zdefiniowano również klasę narzędzi, StringExtensions, która ma dwie metody:The example also defines a utility class, StringExtensions, that has two methods:

  • ConStart, w którym są wyświetlane ciągi zaczynające się od spółgłoski.ConStart, which displays strings that begin with a consonant.

  • VowelStart, w którym są wyświetlane ciągi zaczynające się od samogłosek.VowelStart, which displays strings that begin with a vowel.

Należy zauważyć, że obie metody zawierają jeden parametr ciągu i zwraca void.Note that both methods include a single string parameter and return void. Innymi słowy, obie metody można przypisać do delegata CheckAndDisplayDelegate.In other words, both methods can be assigned to the CheckAndDisplayDelegate delegate.

Metoda Test.Main jest punktem wejścia aplikacji.The Test.Main method is the application entry point. Tworzy wystąpienie obiektu StringContainer, wypełnia je za pomocą ciągów, a następnie utworzy dwa CheckAndDisplayDelegate delegatów, conStart i vowelStart, które wywołują pojedynczą metodę.It instantiates a StringContainer object, populates it with strings, and creates two CheckAndDisplayDelegate delegates, conStart and vowelStart, that invoke a single method. Następnie wywołuje metodę Delegate.Combine, aby utworzyć delegata multipleDelegates, który początkowo zawiera ConStart i VowelStart delegatów.It then calls the Delegate.Combine method to create the multipleDelegates delegate, which initially contains the ConStart and VowelStart delegates. Należy pamiętać, że gdy multipleDelegates delegat jest wywoływany, wyświetla wszystkie ciągi w kolekcji w ich oryginalnej kolejności.Note that when the multipleDelegates delegate is invoked, it displays all the strings in the collection in their original order. Jest to spowodowane tym, że każda litera jest przenoszona oddzielnie do każdego delegata, a każda z nich spełnia kryteria filtrowania tylko jednego z dwóch delegatów.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. Na koniec po wywołaniach do Delegate.Remove i Delegate.CombinemultipleDelegates zawiera dwóch delegatów conStart.Finally, after calls to Delegate.Remove and Delegate.Combine, multipleDelegates contains two conStart delegates. Gdy jest wywoływana, każdy ciąg w obiekcie StringContainer jest wyświetlany dwa razy.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

Uwagi

MulticastDelegate jest klasą specjalną.MulticastDelegate is a special class. Kompilatory i inne narzędzia mogą pochodzić od tej klasy, ale nie można ich jawnie dziedziczyć.Compilers and other tools can derive from this class, but you cannot derive from it explicitly. Ta sama wartość jest prawdziwa dla klasy Delegate.The same is true of the Delegate class.

Oprócz metod, które dziedziczą typy z MulticastDelegate, środowisko uruchomieniowe języka wspólnego udostępnia dwie metody specjalne: BeginInvoke i EndInvoke.In addition to the methods that delegate types inherit from MulticastDelegate, the common language runtime provides two special methods: BeginInvoke and EndInvoke. Aby uzyskać więcej informacji na temat tych metod, zobacz Asynchroniczne wywoływanie metod synchronicznych.For more information about these methods, see Calling Synchronous Methods Asynchronously.

MulticastDelegate ma połączoną listę delegatów, nazywaną listą wywołania, składającą się z co najmniej jednego elementu.A MulticastDelegate has a linked list of delegates, called an invocation list, consisting of one or more elements. Gdy delegat multiemisji jest wywoływany, Delegaty na liście wywołań są wywoływane synchronicznie w kolejności, w jakiej są wyświetlane.When a multicast delegate is invoked, the delegates in the invocation list are called synchronously in the order in which they appear. Jeśli wystąpi błąd podczas wykonywania listy, zgłaszany jest wyjątek.If an error occurs during execution of the list then an exception is thrown.

Konstruktory

MulticastDelegate(Object, String)

Inicjuje nowe wystąpienie klasy MulticastDelegate klasy.Initializes a new instance of the MulticastDelegate class.

MulticastDelegate(Type, String)

Inicjuje nowe wystąpienie klasy MulticastDelegate klasy.Initializes a new instance of the MulticastDelegate class.

Właściwości

Method

Pobiera metodę reprezentowaną przez delegata.Gets the method represented by the delegate.

(Odziedziczone po Delegate)
Target

Pobiera wystąpienie klasy, dla którego bieżący delegat wywołuje metodę wystąpienia.Gets the class instance on which the current delegate invokes the instance method.

(Odziedziczone po Delegate)

Metody

Clone()

Tworzy skróconą kopię delegata.Creates a shallow copy of the delegate.

(Odziedziczone po Delegate)
CombineImpl(Delegate)

Łączy ten Delegate z określonym Delegate w celu utworzenia nowego obiektu delegowanego.Combines this Delegate with the specified Delegate to form a new delegate.

DynamicInvoke(Object[])

Dynamicznie wywołuje (późne wiązanie) metodę reprezentowaną przez bieżącego delegata.Dynamically invokes (late-bound) the method represented by the current delegate.

(Odziedziczone po Delegate)
DynamicInvokeImpl(Object[])

Przetwarza pełną listę wywołań.Processes the full invocation list.

Equals(Object)

Określa, czy ten delegat multiemisji i określony obiekt są równe.Determines whether this multicast delegate and the specified object are equal.

GetHashCode()

Zwraca kod skrótu dla tego wystąpienia.Returns the hash code for this instance.

GetInvocationList()

Zwraca listę wywołań tego delegata multiemisji w kolejności wywoływania.Returns the invocation list of this multicast delegate, in invocation order.

GetMethodImpl()

Zwraca metodę statyczną reprezentowaną przez bieżącą MulticastDelegate.Returns a static method represented by the current MulticastDelegate.

GetObjectData(SerializationInfo, StreamingContext)

Wypełnia obiekt SerializationInfo wszystkimi danymi, które są konieczne do serializacji tego wystąpienia.Populates a SerializationInfo object with all the data needed to serialize this instance.

GetType()

Pobiera Type bieżącego wystąpienia.Gets the Type of the current instance.

(Odziedziczone po Object)
MemberwiseClone()

Tworzy skróconą kopię bieżącego Object.Creates a shallow copy of the current Object.

(Odziedziczone po Object)
RemoveImpl(Delegate)

Usuwa element z listy wywołań tego MulticastDelegate, który jest równy podanemu obiektowi delegowanemu.Removes an element from the invocation list of this MulticastDelegate that is equal to the specified delegate.

ToString()

Zwraca ciąg, który reprezentuje bieżący obiekt.Returns a string that represents the current object.

(Odziedziczone po Object)

Operatory

Equality(MulticastDelegate, MulticastDelegate)

Określa, czy dwa obiekty MulticastDelegate są równe.Determines whether two MulticastDelegate objects are equal.

Inequality(MulticastDelegate, MulticastDelegate)

Określa, czy dwa MulticastDelegate obiekty nie są równe.Determines whether two MulticastDelegate objects are not equal.

Metody rozszerzania

GetMethodInfo(Delegate)

Pobiera obiekt, który reprezentuje metodę reprezentowaną przez określony delegat.Gets an object that represents the method represented by the specified delegate.

Dotyczy