Action<T1,T2,T3,T4> Delegat

Definicja

Hermetyzuje metodę, która ma cztery parametry i nie zwraca wartości.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)

Parametry typu

T1

Typ pierwszego parametru metody, który jest hermetyzowany przez ten delegat.The type of the first parameter of the method that this delegate encapsulates.

T2

Typ drugiego parametru metody, który jest hermetyzowany przez ten delegat.The type of the second parameter of the method that this delegate encapsulates.

T3

Typ trzeciego parametru metody, który jest hermetyzowany przez ten delegat.The type of the third parameter of the method that this delegate encapsulates.

T4

Typ czwartego parametru metody, który jest hermetyzowany przez ten delegat.The type of the fourth parameter of the method that this delegate encapsulates.

Parametry

arg1

Pierwszy parametr metody, która jest hermetyzowana przez ten delegat.The first parameter of the method that this delegate encapsulates.

arg2

Drugi parametr metody, która jest hermetyzowana przez ten delegat.The second parameter of the method that this delegate encapsulates.

arg3

Trzeci parametr metody, która jest hermetyzowana przez ten delegat.The third parameter of the method that this delegate encapsulates.

arg4

Czwarty parametr metody, która jest hermetyzowana przez ten delegat.The fourth parameter of the method that this delegate encapsulates.

Dziedziczenie
Action<T1,T2,T3,T4>

Uwagi

Można użyć delegata Action<T1,T2,T3,T4>, aby przekazać metodę jako parametr bez jawnego deklarowania niestandardowego delegata.You can use the Action<T1,T2,T3,T4> delegate to pass a method as a parameter without explicitly declaring a custom delegate. Metoda hermetyzowana musi odpowiadać sygnaturze metody zdefiniowanej przez tego delegata.The encapsulated method must correspond to the method signature that is defined by this delegate. Oznacza to, że metoda hermetyzowana musi mieć cztery parametry, które są do niego przesyłane przez wartość i nie może zwracać wartości.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. (W C#, metoda musi zwracać void.(In C#, the method must return void. W Visual Basic musi on być zdefiniowany przez Sub...End SubIn Visual Basic, it must be defined by the SubEnd Sub Konstruuj.construct. Może być również metodą zwracającą wartość, która jest ignorowana.) Zazwyczaj taka metoda jest używana do wykonywania operacji.It can also be a method that returns a value that is ignored.) Typically, such a method is used to perform an operation.

Uwaga

Aby odwołać się do metody, która ma cztery parametry i zwraca wartość, należy zamiast tego użyć delegata generycznego Func<T1,T2,T3,T4,TResult>.To reference a method that has four parameters and returns a value, use the generic Func<T1,T2,T3,T4,TResult> delegate instead.

W przypadku korzystania z delegata Action<T1,T2,T3,T4> nie trzeba jawnie definiować delegata, który hermetyzuje metodę z czterema parametrami.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. Na przykład poniższy kod jawnie deklaruje delegata o nazwie StringCopy i przypisuje odwołanie do metody CopyStrings do jego wystąpienia delegata.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

Poniższy przykład upraszcza ten kod, tworząc wystąpienie delegata Action<T1,T2,T3,T4>, zamiast jawnie definiując nowy delegat i przypisując nazwaną metodę.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

Można również użyć delegata Action<T1,T2,T3,T4> z metodami anonimowymi C#w, jak pokazano w poniższym przykładzie.You can also use the Action<T1,T2,T3,T4> delegate with anonymous methods in C#, as the following example illustrates. (Aby uzyskać wprowadzenie do metod anonimowych, zobacz metody anonimowe).(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]);
   }
}

Można również przypisać wyrażenie lambda do wystąpienia Action<T1,T2,T3,T4> delegata, jak pokazano w poniższym przykładzie.You can also assign a lambda expression to an Action<T1,T2,T3,T4> delegate instance, as the following example illustrates. (Aby uzyskać wprowadzenie do wyrażeń lambda, zobacz lambda Expressions).(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

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

Zobacz też