MulticastDelegate MulticastDelegate MulticastDelegate MulticastDelegate Class

Определение

Представляет групповой делегат, то есть делегат, имеющий в своем списке вызовов более одного элемента. 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
Наследование
MulticastDelegateMulticastDelegateMulticastDelegateMulticastDelegate
Атрибуты

Примеры

В следующем примере определяется класс, StringContainer, который включает коллекцию строк.The following example defines a class, StringContainer, which includes a collection of strings. Один из его членов является CheckAndDisplayDelegate делегат, который используется для отображения строк, которые хранятся в StringContainer объекта, которые удовлетворяют определенным условиям.One of its members is the CheckAndDisplayDelegate delegate, which is used to display strings stored in a StringContainer object that satisfy particular criteria. Делегат принимает одну строку в качестве параметра и возвращает void (или, в Visual Basic это Sub процедуры).The delegate takes a single string as a parameter and returns void (or, in Visual Basic, it's a Sub procedure). Он также включает метод, DisplayAllQualified, который имеет один параметр, CheckAndDisplayDelegate делегировать.It also includes a method, DisplayAllQualified, that has a single parameter, a CheckAndDisplayDelegate delegate. Это позволяет вызывать метод и для отображения набора строк, которые фильтруются на основе методов, которые содержит делегат.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.

В примере также определяется служебный класс, StringExtensions, который имеет два метода:The example also defines a utility class, StringExtensions, that has two methods:

  • ConStart, которая отображает строки, которые начинаются с согласной.ConStart, which displays strings that begin with a consonant.

  • VowelStart, которая отображает строки, начинающиеся с гласных.VowelStart, which displays strings that begin with a vowel.

Обратите внимание, что оба метода включают один строковый параметр и возвращает void.Note that both methods include a single string parameter and return void. Другими словами, оба метода могут быть назначены CheckAndDisplayDelegate делегировать.In other words, both methods can be assigned to the CheckAndDisplayDelegate delegate.

Test.Main Метод является точкой входа приложения.The Test.Main method is the application entry point. Он создает экземпляр StringContainer , заполняет ее строки и создает два CheckAndDisplayDelegate делегаты, conStart и vowelStart, что вызвать один метод.It instantiates a StringContainer object, populates it with strings, and creates two CheckAndDisplayDelegate delegates, conStart and vowelStart, that invoke a single method. Затем он вызывает Delegate.Combine метод для создания multipleDelegates делегат, который изначально содержит ConStart и VowelStart делегатов.It then calls the Delegate.Combine method to create the multipleDelegates delegate, which initially contains the ConStart and VowelStart delegates. Обратите внимание, что при multipleDelegates вызове делегата, на экран выводятся все строки в коллекции в исходном порядке.Note that when the multipleDelegates delegate is invoked, it displays all the strings in the collection in their original order. Это потому, что каждая буква передается отдельно для каждого делегата, и каждая буква соответствует критериям фильтрации только одного из двух делегатов.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. Наконец, после обращения к Delegate.Remove и Delegate.Combine, multipleDelegates содержит два conStart делегатов.Finally, after calls to Delegate.Remove and Delegate.Combine, multipleDelegates contains two conStart delegates. При вызове, каждая строка в StringContainer объект отображается дважды.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

Комментарии

MulticastDelegate — Это специальный класс.MulticastDelegate is a special class. Компиляторы и другие средства могут наследовать от этого класса, но вы не можете заменить его явным образом.Compilers and other tools can derive from this class, but you cannot derive from it explicitly. То же самое относится и к Delegate класса.The same is true of the Delegate class.

В дополнение к методам, которые делегируют типы наследуют от MulticastDelegate, среда CLR предоставляет два специальных методов: BeginInvoke и EndInvoke.In addition to the methods that delegate types inherit from MulticastDelegate, the common language runtime provides two special methods: BeginInvoke and EndInvoke. Дополнительные сведения об этих методах см. в разделе асинхронный вызов синхронных методов.For more information about these methods, see Calling Synchronous Methods Asynchronously.

Объект MulticastDelegate имеет связанный список делегатов, называемый списком вызовов, состоящий из одного или нескольких элементов.A MulticastDelegate has a linked list of delegates, called an invocation list, consisting of one or more elements. При вызове многоадресного делегата, делегаты в списке вызовов вызываются в порядке, в котором они отображаются одновременно.When a multicast delegate is invoked, the delegates in the invocation list are called synchronously in the order in which they appear. При возникновении ошибки во время выполнения списка, возникает исключение.If an error occurs during execution of the list then an exception is thrown.

Конструкторы

MulticastDelegate(Object, String) MulticastDelegate(Object, String) MulticastDelegate(Object, String) MulticastDelegate(Object, String)

Инициализирует новый экземпляр класса MulticastDelegate. Initializes a new instance of the MulticastDelegate class.

MulticastDelegate(Type, String) MulticastDelegate(Type, String) MulticastDelegate(Type, String) MulticastDelegate(Type, String)

Инициализирует новый экземпляр класса MulticastDelegate. Initializes a new instance of the MulticastDelegate class.

Методы

Clone() Clone() Clone() Clone()

Создает неполную копию делегата.Creates a shallow copy of the delegate.

(Inherited from Delegate)
CombineImpl(Delegate) CombineImpl(Delegate) CombineImpl(Delegate) CombineImpl(Delegate)

Объединяет данный делегат Delegate с указанным делегатом Delegate для формирования нового делегата. Combines this Delegate with the specified Delegate to form a new delegate.

DynamicInvoke(Object[]) DynamicInvoke(Object[]) DynamicInvoke(Object[]) DynamicInvoke(Object[])

Динамически (с поздней привязкой) вызывает метод, представленный текущим делегатом.Dynamically invokes (late-bound) the method represented by the current delegate.

(Inherited from Delegate)
DynamicInvokeImpl(Object[]) DynamicInvokeImpl(Object[]) DynamicInvokeImpl(Object[]) DynamicInvokeImpl(Object[])

Обрабатывает полный список вызовов. Processes the full invocation list.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Определяет, равны ли этот групповой делегат и указанный объект. Determines whether this multicast delegate and the specified object are equal.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Возвращает хэш-код данного экземпляра. Returns the hash code for this instance.

GetInvocationList() GetInvocationList() GetInvocationList() GetInvocationList()

Возвращает список вызовов данного группового делегата в порядке вызова. Returns the invocation list of this multicast delegate, in invocation order.

GetMethodImpl() GetMethodImpl() GetMethodImpl() GetMethodImpl()

Возвращает статический метод, представленный текущим MulticastDelegate. Returns a static method represented by the current MulticastDelegate.

GetObjectData(SerializationInfo, StreamingContext) GetObjectData(SerializationInfo, StreamingContext) GetObjectData(SerializationInfo, StreamingContext) GetObjectData(SerializationInfo, StreamingContext)

Заполняет объект SerializationInfo всеми данными, необходимыми для сериализации данного экземпляра. Populates a SerializationInfo object with all the data needed to serialize this instance.

GetType() GetType() GetType() GetType()

Возвращает объект Type для текущего экземпляра. Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Создает неполную копию текущего объекта Object. Creates a shallow copy of the current Object.

(Inherited from Object)
RemoveImpl(Delegate) RemoveImpl(Delegate) RemoveImpl(Delegate) RemoveImpl(Delegate)

Удаляет элемент, равный указанному делегату, из списка вызовов данного MulticastDelegate. Removes an element from the invocation list of this MulticastDelegate that is equal to the specified delegate.

ToString() ToString() ToString() ToString()

Возвращает строку, представляющую текущий объект. Returns a string that represents the current object.

(Inherited from Object)

Операторы

Equality(MulticastDelegate, MulticastDelegate) Equality(MulticastDelegate, MulticastDelegate) Equality(MulticastDelegate, MulticastDelegate) Equality(MulticastDelegate, MulticastDelegate)

Определяет равенство двух объектов MulticastDelegate. Determines whether two MulticastDelegate objects are equal.

Inequality(MulticastDelegate, MulticastDelegate) Inequality(MulticastDelegate, MulticastDelegate) Inequality(MulticastDelegate, MulticastDelegate) Inequality(MulticastDelegate, MulticastDelegate)

Определяет, отличаются ли два объекта MulticastDelegate. Determines whether two MulticastDelegate objects are not equal.

Свойства

Method Method Method Method

Возвращает метод, представленный делегатом.Gets the method represented by the delegate.

(Inherited from Delegate)
Target Target Target Target

Возвращает экземпляр класса, метод которого вызывает текущий делегат.Gets the class instance on which the current delegate invokes the instance method.

(Inherited from Delegate)

Extension Methods

GetMethodInfo(Delegate) GetMethodInfo(Delegate) GetMethodInfo(Delegate) GetMethodInfo(Delegate)

Получает объект, представляющий метод, представленный указанным делегатом. Gets an object that represents the method represented by the specified delegate.

Применяется к