Action<T1,T2,T3,T4> Delegat

Definition

Kapselt eine Methode, die über vier Parameter verfügt und keinen Wert zurückgibt.Encapsulates a method that has four parameters and does not return a value.

generic <typename T1, typename T2, typename T3, typename T4>
public delegate void Action(T1 arg1, T2 arg2, T3 arg3, T4 arg4);
public delegate void Action<in T1,in T2,in T3,in T4>(T1 arg1, T2 arg2, T3 arg3, T4 arg4);
type Action<'T1, 'T2, 'T3, 'T4> = delegate of 'T1 * 'T2 * 'T3 * 'T4 -> unit
Public Delegate Sub Action(Of In T1, In T2, In T3, In T4)(arg1 As T1, arg2 As T2, arg3 As T3, arg4 As T4)

Typparameter

T1

Der Typ des ersten Parameters der Methode, die dieser Delegat kapselt.The type of the first parameter of the method that this delegate encapsulates.

T2

Der Typ des zweiten Parameters der Methode, die dieser Delegat kapselt.The type of the second parameter of the method that this delegate encapsulates.

T3

Der Typ des dritten Parameters der Methode, die dieser Delegat kapselt.The type of the third parameter of the method that this delegate encapsulates.

T4

Der Typ des vierten Parameters der Methode, die dieser Delegat kapselt.The type of the fourth parameter of the method that this delegate encapsulates.

Parameter

arg1

Der erste Parameter der Methode, die dieser Delegat kapselt.The first parameter of the method that this delegate encapsulates.

arg2

Der zweite Parameter der Methode, die dieser Delegat kapselt.The second parameter of the method that this delegate encapsulates.

arg3

Der dritte Parameter der Methode, die dieser Delegat kapselt.The third parameter of the method that this delegate encapsulates.

arg4

Der vierte Parameter der Methode, die dieser Delegat kapselt.The fourth parameter of the method that this delegate encapsulates.

Vererbung
Action<T1,T2,T3,T4>

Hinweise

Sie können den Action<T1,T2,T3,T4> -Delegaten verwenden, um eine Methode als Parameter zu übergeben, ohne explizit einen benutzerdefinierten Delegaten zu deklarieren.You can use the Action<T1,T2,T3,T4> delegate to pass a method as a parameter without explicitly declaring a custom delegate. Die gekapselte Methode muss der Methoden Signatur entsprechen, die von diesem Delegaten definiert wird.The encapsulated method must correspond to the method signature that is defined by this delegate. Dies bedeutet, dass die gekapselte Methode über vier Parameter verfügen muss, die alle als Wert an Sie übermittelt werden, und Sie darf keinen Wert zurückgeben.This means that the encapsulated method must have four parameters that are all passed to it by value, and it must not return a value. (In C#muss die-Methode zurück voidgeben.(In C#, the method must return void. In Visual Basic muss Sie von der Sub...End SubIn Visual Basic, it must be defined by the SubEnd Sub Erstellen.construct. Es kann auch eine Methode sein, die einen Wert zurückgibt, der ignoriert wird.) In der Regel wird eine solche Methode verwendet, um einen Vorgang auszuführen.It can also be a method that returns a value that is ignored.) Typically, such a method is used to perform an operation.

Hinweis

Verwenden Sie stattdessen den generischen Func<T1,T2,T3,T4,TResult> Delegaten, um auf eine Methode zu verweisen, die über vier Parameter verfügt und einen Wert zurückgibt.To reference a method that has four parameters and returns a value, use the generic Func<T1,T2,T3,T4,TResult> delegate instead.

Wenn Sie den Action<T1,T2,T3,T4> -Delegaten verwenden, müssen Sie nicht explizit einen Delegaten definieren, der eine Methode mit vier Parametern kapselt.When you use the Action<T1,T2,T3,T4> delegate, you do not have to explicitly define a delegate that encapsulates a method with four parameters. Der folgende Code deklariert z. b. explizit einen Delegaten mit dem Namen StringCopy und weist der Delegatinstanz einen Verweis auf die CopyStrings -Methode zu.For example, the following code explicitly declares a delegate named StringCopy and assigns a reference to the CopyStrings method to its delegate instance.

using System;

delegate void StringCopy(string[] stringArray1, 
                         string[] stringArray2, 
                         int indexToStart,
                         int numberToCopy);
                         
public class TestDelegate
{
   public static void Main()
   {
      string[] ordinals = {"First", "Second", "Third", "Fourth", "Fifth", 
                           "Sixth", "Seventh", "Eighth", "Ninth", "Tenth"};
      string[] copiedOrdinals = new string[ordinals.Length];           
      StringCopy copyOperation = CopyStrings;
      copyOperation(ordinals, copiedOrdinals, 3, 5);
      foreach (string ordinal in copiedOrdinals)
         Console.WriteLine(String.IsNullOrEmpty(ordinal) ? "<None>" : ordinal);
   }

   private static void CopyStrings(string[] source, string[] target, 
                                   int startPos, int number)
   {
      if (source.Length != target.Length) 
         throw new IndexOutOfRangeException("The source and target arrays must have the same number of elements.");

      for (int ctr = startPos; ctr <= startPos + number - 1; ctr++)
         target[ctr] = String.Copy(source[ctr]);
   }
}
Delegate Sub StringCopy(stringArray1() As String, _
                        stringArray2() As String, _
                        indexToStart As Integer, _
                        numberToCopy As Integer)

Module TestDelegate
   Public Sub Main()
      Dim ordinals() As String = {"First", "Second", "Third", "Fourth", _
                                  "Fifth", "Sixth", "Seventh", "Eighth", _
                                  "Ninth", "Tenth"}
      Dim copiedOrdinals(ordinals.Length - 1) As String
      Dim copyOperation As StringCopy = AddressOf CopyStrings
      copyOperation(ordinals, copiedOrdinals, 3, 5)
      For Each ordinal As String In copiedOrdinals
         Console.WriteLine(ordinal)
      Next    
   End Sub
   
   Private Sub CopyStrings(source() As String, target() As String, _
                           startPos As Integer, number As Integer)
      If source.Length <> target.Length Then 
         Throw New IndexOutOfRangeException("The source and target arrays" & _
                   " must have the same number of elements.")
      End If
      For ctr As Integer = startPos to startpos + number  - 1
         target(ctr) = String.Copy(source(ctr))
      Next
   End Sub
End Module

Im folgenden Beispiel wird dieser Code vereinfacht, indem der Action<T1,T2,T3,T4> Delegat instanziiert wird, anstatt explizit einen neuen Delegaten zu definieren und ihm eine benannte Methode zuzuweisen.The following example simplifies this code by instantiating the Action<T1,T2,T3,T4> delegate instead of explicitly defining a new delegate and assigning a named method to it.

using System;

public class TestAction4
{
   public static void Main()
   {
      string[] ordinals = {"First", "Second", "Third", "Fourth", "Fifth", 
                           "Sixth", "Seventh", "Eighth", "Ninth", "Tenth"};
      string[] copiedOrdinals = new string[ordinals.Length];           
      Action<string[], string[], int, int> copyOperation = CopyStrings;
      copyOperation(ordinals, copiedOrdinals, 3, 5);
      foreach (string ordinal in copiedOrdinals)
         Console.WriteLine(String.IsNullOrEmpty(ordinal) ? "<None>" : ordinal);
   }

   private static void CopyStrings(string[] source, string[] target, 
                                   int startPos, int number)
   {
      if (source.Length != target.Length) 
         throw new IndexOutOfRangeException("The source and target arrays must have the same number of elements.");

      for (int ctr = startPos; ctr <= startPos + number - 1; ctr++)
         target[ctr] = String.Copy(source[ctr]);
   }
}
Module TestAction4
   Public Sub Main()
      Dim ordinals() As String = {"First", "Second", "Third", "Fourth", _
                                  "Fifth", "Sixth", "Seventh", "Eighth", _
                                  "Ninth", "Tenth"}
      Dim copiedOrdinals(ordinals.Length - 1) As String
      Dim copyOperation As Action(Of String(), String(), Integer, Integer) = _
                           AddressOf CopyStrings
      copyOperation(ordinals, copiedOrdinals, 3, 5)
      For Each ordinal As String In copiedOrdinals
         Console.WriteLine(ordinal)
      Next    
   End Sub
   
   Private Sub CopyStrings(source() As String, target() As String, _
                           startPos As Integer, number As Integer)
      If source.Length <> target.Length Then 
         Throw New IndexOutOfRangeException("The source and target arrays" & _
                   " must have the same number of elements.")
      End If
      For ctr As Integer = startPos to startpos + number  - 1
         target(ctr) = String.Copy(source(ctr))
      Next
   End Sub
End Module

Sie können den Action<T1,T2,T3,T4> Delegaten auch mit anonymen Methoden in C#verwenden, wie im folgenden Beispiel veranschaulicht.You can also use the Action<T1,T2,T3,T4> delegate with anonymous methods in C#, as the following example illustrates. (Eine Einführung zu anonymen Methoden finden Sie unter Anonyme Methoden.)(For an introduction to anonymous methods, see Anonymous Methods.)

using System;

public class TestAnonymousMethod
{
   public static void Main()
   {
      string[] ordinals = {"First", "Second", "Third", "Fourth", "Fifth", 
                           "Sixth", "Seventh", "Eighth", "Ninth", "Tenth"};
      string[] copiedOrdinals = new string[ordinals.Length];           
      Action<string[], string[], int, int> copyOperation = 
                                           delegate(string[] s1, string[] s2, 
                                           int pos, int num) 
                                { CopyStrings(s1, s2, pos, num); };  
      copyOperation(ordinals, copiedOrdinals, 3, 5);
      foreach (string ordinal in copiedOrdinals)
         Console.WriteLine(String.IsNullOrEmpty(ordinal) ? "<None>" : ordinal);
   }

   private static void CopyStrings(string[] source, string[] target, 
                                   int startPos, int number)
   {
      if (source.Length != target.Length) 
         throw new IndexOutOfRangeException("The source and target arrays must have the same number of elements.");

      for (int ctr = startPos; ctr <= startPos + number - 1; ctr++)
         target[ctr] = String.Copy(source[ctr]);
   }
}

Sie können einem Delegatinstanz auch einen Lambda Action<T1,T2,T3,T4> -Ausdruck zuweisen, wie im folgenden Beispiel veranschaulicht.You can also assign a lambda expression to an Action<T1,T2,T3,T4> delegate instance, as the following example illustrates. (Eine Einführung in Lambda-Ausdrücke finden Sie unter Lambda-Ausdrücke.)(For an introduction to lambda expressions, see Lambda Expressions.)

using System;

public class TestLambdaExpression
{
   public static void Main()
   {
      string[] ordinals = {"First", "Second", "Third", "Fourth", "Fifth", 
                           "Sixth", "Seventh", "Eighth", "Ninth", "Tenth"};
      string[] copiedOrdinals = new string[ordinals.Length];           
      Action<string[], string[], int, int> copyOperation = (s1, s2, pos, num)
                                           => CopyStrings(s1, s2, pos, num);  
      copyOperation(ordinals, copiedOrdinals, 3, 5);
      foreach (string ordinal in copiedOrdinals)
         Console.WriteLine(String.IsNullOrEmpty(ordinal) ? "<None>" : ordinal);
   }

   private static void CopyStrings(string[] source, string[] target, 
                                   int startPos, int number)
   {
      if (source.Length != target.Length) 
         throw new IndexOutOfRangeException("The source and target arrays must have the same number of elements.");

      for (int ctr = startPos; ctr <= startPos + number - 1; ctr++)
         target[ctr] = String.Copy(source[ctr]);
   }
}
Public Module TestLambdaExpression
   Public Sub Main()
      Dim ordinals() As String = {"First", "Second", "Third", "Fourth", "Fifth", _ 
                           "Sixth", "Seventh", "Eighth", "Ninth", "Tenth"}
      Dim copiedOrdinals(ordinals.Length - 1) As String           
      Dim copyOperation As Action(Of String(), String(), Integer, Integer) = _
                           Sub(s1, s2, pos, num) CopyStrings(s1, s2, pos, num)  
      copyOperation(ordinals, copiedOrdinals, 3, 5)
      For Each ordinal As String In copiedOrdinals
         If String.IsNullOrEmpty(ordinal) Then
            Console.WriteLine("<None>")
         Else
            Console.WriteLine(ordinal)
         End If
      Next   
   End Sub

   Private Function CopyStrings(source() As String, target() As String, _ 
                                startPos As Integer, number As Integer) As Integer
      If source.Length <> target.Length Then 
         throw new IndexOutOfRangeException("The source and target arrays must have the same number of elements.")
      End If
      
      For ctr As Integer = startPos To startPos + number - 1
         target(ctr) = String.Copy(source(ctr))
      Next
      Return number
   End Function
End Module
' The example displays the following output:
'       Fourth
'       Fifth
'       Sixth
'       Seventh
'       Eighth

Erweiterungsmethoden

GetMethodInfo(Delegate)

Ruft ein Objekt ab, das die Methode darstellt, die vom angegebenen Delegaten dargestellt wird.Gets an object that represents the method represented by the specified delegate.

Gilt für:

Siehe auch