MulticastDelegate MulticastDelegate MulticastDelegate MulticastDelegate Class

Definice

Představuje delegáta vícesměrového vysílání. To znamená, že delegát, který může mít více než jeden element v jeho vyvolávacím seznamu.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
Dědičnost
MulticastDelegateMulticastDelegateMulticastDelegateMulticastDelegate
Atributy

Příklady

Následující příklad definuje třídu, StringContainer, která obsahuje kolekci řetězců.The following example defines a class, StringContainer, which includes a collection of strings. Jednou z jejích členů je CheckAndDisplayDelegate delegáta, který se používá k zobrazení řetězce uložené v StringContainer objektu, která splňují konkrétní kritéria.One of its members is the CheckAndDisplayDelegate delegate, which is used to display strings stored in a StringContainer object that satisfy particular criteria. Delegát přebírá jako parametr jeden řetězec a vrací void (nebo v jazyce Visual Basic je Sub postupu).The delegate takes a single string as a parameter and returns void (or, in Visual Basic, it's a Sub procedure). Zahrnuje také metodu, DisplayAllQualified, která má jeden parametr, CheckAndDisplayDelegate delegovat.It also includes a method, DisplayAllQualified, that has a single parameter, a CheckAndDisplayDelegate delegate. Díky tomu metodu, která se má volat a chcete-li zobrazit sadu řetězců, které jsou filtrovány podle metody, které obsahuje delegát.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.

Tento příklad také definuje třídu nástroj StringExtensions, který má dvě metody:The example also defines a utility class, StringExtensions, that has two methods:

  • ConStart, které zobrazí řetězce, které začínají souhláska.ConStart, which displays strings that begin with a consonant.

  • VowelStart, které zobrazí řetězce, která začínají samohláskou.VowelStart, which displays strings that begin with a vowel.

Mějte na paměti, že obě metody zahrnovat parametr jeden řetězec a vrátit void.Note that both methods include a single string parameter and return void. Jinými slovy, obě metody lze přiřadit CheckAndDisplayDelegate delegovat.In other words, both methods can be assigned to the CheckAndDisplayDelegate delegate.

Test.Main Metoda je vstupní bod aplikace.The Test.Main method is the application entry point. Vytvoření instance StringContainer objektů, naplní ho s řetězci a vytvoří dva CheckAndDisplayDelegate delegáty, conStart a vowelStart, který vyvolání jedné metody.It instantiates a StringContainer object, populates it with strings, and creates two CheckAndDisplayDelegate delegates, conStart and vowelStart, that invoke a single method. Poté zavolá Delegate.Combine metodu pro vytvoření multipleDelegates delegáta, který původně obsahuje ConStart a VowelStart delegátů.It then calls the Delegate.Combine method to create the multipleDelegates delegate, which initially contains the ConStart and VowelStart delegates. Všimněte si, že multipleDelegates je vyvolán delegát, zobrazí se všechny řetězce v kolekci v původním pořadí.Note that when the multipleDelegates delegate is invoked, it displays all the strings in the collection in their original order. Je to proto, že každé písmeno ke všem delegátům předána samostatně a každé písmeno splňuje kritéria filtrování pouze jednoho ze dvou delegátů.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. Nakonec po volání Delegate.Remove a Delegate.Combine, multipleDelegates obsahuje dva conStart delegátů.Finally, after calls to Delegate.Remove and Delegate.Combine, multipleDelegates contains two conStart delegates. Když je vyvolána, každý řetězec v StringContainer objektu se zobrazí dvakrát.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

Poznámky

MulticastDelegate je speciální třídy.MulticastDelegate is a special class. Kompilátory a další nástroje lze odvodit z této třídy, ale nemůže odvozovat z něj explicitně.Compilers and other tools can derive from this class, but you cannot derive from it explicitly. Totéž platí o Delegate třídy.The same is true of the Delegate class.

Kromě metod, které typy delegátů dědit z MulticastDelegate, modul common language runtime nabízí dvě metody speciální: BeginInvoke a EndInvoke.In addition to the methods that delegate types inherit from MulticastDelegate, the common language runtime provides two special methods: BeginInvoke and EndInvoke. Další informace o těchto metodách v tématu voláním synchronní metody asynchronně.For more information about these methods, see Calling Synchronous Methods Asynchronously.

A MulticastDelegate má odkazovaného seznamu delegátů, volá se, seznam volání, který se skládá z jednoho nebo více prvků.A MulticastDelegate has a linked list of delegates, called an invocation list, consisting of one or more elements. Když uživatel vyvolá delegáta vícesměrového vysílání, delegáti v seznamu vyvolání jsou v pořadí, v jakém jsou uvedeny volat synchronně.When a multicast delegate is invoked, the delegates in the invocation list are called synchronously in the order in which they appear. Pokud dojde k chybě při spuštění seznamu je vyvolána výjimka.If an error occurs during execution of the list then an exception is thrown.

Konstruktory

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

Inicializuje novou instanci třídy MulticastDelegate třídy.Initializes a new instance of the MulticastDelegate class.

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

Inicializuje novou instanci třídy MulticastDelegate třídy.Initializes a new instance of the MulticastDelegate class.

Metody

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

Vytvoří Mělkou kopii delegáta.Creates a shallow copy of the delegate.

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

Kombinuje to Delegate se zadaným Delegate k vytvoření nového delegáta.Combines this Delegate with the specified Delegate to form a new delegate.

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

Dynamicky (s pozdní vazbou) vyvolá metodu reprezentovanou aktuální delegáta.Dynamically invokes (late-bound) the method represented by the current delegate.

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

Zpracuje úplnou vyvolání seznamu.Processes the full invocation list.

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

Určuje, zda tento delegát vícesměrového vysílání a zadaný objekt rovná.Determines whether this multicast delegate and the specified object are equal.

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

Vrátí kód hash této instance.Returns the hash code for this instance.

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

Vrátí seznamu vyvolání tohoto delegáta vícesměrového vysílání v pořadí volání.Returns the invocation list of this multicast delegate, in invocation order.

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

Vrátí statickou metodu reprezentované aktuální MulticastDelegate.Returns a static method represented by the current MulticastDelegate.

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

Naplní SerializationInfo objekt se všechna data potřebná k serializaci této instance.Populates a SerializationInfo object with all the data needed to serialize this instance.

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

Získá Type aktuální instance.Gets the Type of the current instance.

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

Vytvoří Mělkou kopii aktuální Object.Creates a shallow copy of the current Object.

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

Odebere element ze seznamu vyvolání tohoto MulticastDelegate , který je roven zadané delegáta.Removes an element from the invocation list of this MulticastDelegate that is equal to the specified delegate.

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

Vrací řetězec, který představuje aktuální objekt.Returns a string that represents the current object.

(Inherited from Object)

Operátory

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

Určuje, zda dva MulticastDelegate objekty rovnají.Determines whether two MulticastDelegate objects are equal.

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

Určuje, zda dva MulticastDelegate objekty nejsou stejné.Determines whether two MulticastDelegate objects are not equal.

Vlastnosti

Method Method Method Method

Získá metodě reprezentované delegátem.Gets the method represented by the delegate.

(Inherited from Delegate)
Target Target Target Target

Získá instanci třídy, na kterém aktuální delegáta vyvolá metodu instance.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)

Získá objekt, který představuje metodu reprezentovanou zadaného delegáta.Gets an object that represents the method represented by the specified delegate.

Platí pro