Action<T1,T2,T3> Temsilci

Tanım

generic <typename T1, typename T2, typename T3>
public delegate void Action(T1 arg1, T2 arg2, T3 arg3);

public delegate void Action<in T1,in T2,in T3>(T1 arg1, T2 arg2, T3 arg3);

public delegate void Action<T1,T2,T3>(T1 arg1, T2 arg2, T3 arg3);

type Action<'T1, 'T2, 'T3> = delegate of 'T1 * 'T2 * 'T3 -> unit

Public Delegate Sub Action(Of In T1, In T2, In T3)(arg1 As T1, arg2 As T2, arg3 As T3)

Public Delegate Sub Action(Of T1, T2, T3)(arg1 As T1, arg2 As T2, arg3 As T3)

Tür Parametreleri

Parametreler

Açıklamalar

Özel temsilciyi açıkça bildirmeden bir yöntemi parametre olarak geçirmek için Action<T1,T2,T3> temsilcisini kullanabilirsiniz. Kapsüllenen yöntem, bu temsilci tarafından tanımlanan yöntem imzasına karşılık olmalıdır. Bu, kapsüllenmiş yöntemin tümü değere göre geçirilen üç parametreye sahip olması ve bir değer döndürmemesi gerektiği anlamına gelir. (C# dilinde yöntemi voiddöndürmelidir. F# dilinde yöntemin veya işlevin birim döndürmesi gerekir. Visual Basic'te, Sub...End Sub yapısı tarafından tanımlanmalıdır. Yoksayılan bir değer döndüren bir yöntem de olabilir.) Genellikle, böyle bir yöntem bir işlemi gerçekleştirmek için kullanılır.

Action<T1,T2,T3> temsilcisini kullandığınızda, bir yöntemi üç parametreyle kapsülleyen bir temsilciyi açıkça tanımlamanız gerekmez. Örneğin, aşağıdaki kod açıkça StringCopy adlı bir temsilci bildirir ve temsilci örneğine CopyStrings yöntemine bir başvuru atar.

using System;

delegate void StringCopy(string[] stringArray1,
                         string[] stringArray2,
                         int indexToStart);

public class TestDelegate
{
    public static void Main()
    {
        string[] ordinals = ["First", "Second", "Third", "Fourth", "Fifth"];
        string[] copiedOrdinals = new string[ordinals.Length];
        StringCopy copyOperation = CopyStrings;
        copyOperation(ordinals, copiedOrdinals, 3);
        foreach (string ordinal in copiedOrdinals)
            Console.WriteLine(string.IsNullOrEmpty(ordinal) ? "<None>" : ordinal);
    }

    private static void CopyStrings(string[] source, string[] target, int startPos)
    {
        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 <= source.Length - 1; ctr++)
            target[ctr] = source[ctr];
    }
}

open System

type StringCopy = delegate of stringArray1: string [] * 
                              stringArray2: string [] * 
                              indexToStart: int -> unit

let copyStrings (source: string []) (target: string []) startPos =
    if source.Length <> target.Length then
        raise (IndexOutOfRangeException "The source and target arrays must have the same number of elements.")

    for i = startPos to source.Length - 1 do
        target.[i] <- source.[i]

let ordinals = [| "First"; "Second"; "Third"; "Fourth"; "Fifth" |]
let copiedOrdinals: string [] = Array.zeroCreate ordinals.Length

let copyOperation = StringCopy copyStrings

copyOperation.Invoke(ordinals, copiedOrdinals, 3)

for ordinal in copiedOrdinals do
    printfn "%s" (if String.IsNullOrEmpty ordinal then "<None>" else ordinal)

Delegate Sub StringCopy(stringArray1() As String,
                        stringArray2() As String,
                        indexToStart As Integer)

Module TestDelegate
    Public Sub RunIt()
        Dim ordinals() As String = {"First", "Second", "Third", "Fourth", "Fifth"}
        Dim copiedOrdinals(ordinals.Length - 1) As String
        Dim copyOperation As StringCopy = AddressOf CopyStrings
        copyOperation(ordinals, copiedOrdinals, 3)
        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 Sub CopyStrings(source() As String, target() As String, startPos 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 source.Length - 1
            target(ctr) = source(ctr)
        Next
    End Sub
End Module

Aşağıdaki örnek, yeni bir temsilciyi açıkça tanımlamak ve buna adlandırılmış bir yöntem atamak yerine Action<T1,T2,T3> temsilcisinin örneğini oluşturarak bu kodu basitleştirir.

using System;

public class TestAction3
{
    public static void Main()
    {
        string[] ordinals = ["First", "Second", "Third", "Fourth", "Fifth"];
        string[] copiedOrdinals = new string[ordinals.Length];
        Action<string[], string[], int> copyOperation = CopyStrings;
        copyOperation(ordinals, copiedOrdinals, 3);
        foreach (string ordinal in copiedOrdinals)
            Console.WriteLine(string.IsNullOrEmpty(ordinal) ? "<None>" : ordinal);
    }

    private static void CopyStrings(string[] source, string[] target, int startPos)
    {
        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 <= source.Length - 1; ctr++)
            target[ctr] = source[ctr];
    }
}

open System

let copyStrings (source: string []) (target: string []) startPos =
    if source.Length <> target.Length then
        raise (IndexOutOfRangeException "The source and target arrays must have the same number of elements.")

    for i = startPos to source.Length - 1 do
        target.[i] <- source.[i]

let ordinals = [| "First"; "Second"; "Third"; "Fourth"; "Fifth" |]
let copiedOrdinals = Array.zeroCreate<string> ordinals.Length

let copyOperation = Action<_,_,_> copyStrings

copyOperation.Invoke(ordinals, copiedOrdinals, 3)

for ordinal in copiedOrdinals do
    printfn "%s" (if String.IsNullOrEmpty ordinal then "<None>" else ordinal)

Module TestAction3
    Public Sub RunIt()
        Dim ordinals() As String = {"First", "Second", "Third", "Fourth", "Fifth"}
        Dim copiedOrdinals(ordinals.Length - 1) As String
        Dim copyOperation As Action(Of String(), String(), Integer) = AddressOf CopyStrings
        copyOperation(ordinals, copiedOrdinals, 3)
        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 Sub CopyStrings(source() As String, target() As String, startPos 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 source.Length - 1
            target(ctr) = source(ctr)
        Next
    End Sub
End Module

Aşağıdaki örnekte gösterildiği gibi C# dilinde anonim yöntemlerle Action<T1,T2,T3> temsilcisini de kullanabilirsiniz. (Anonim yöntemlere giriş için bkz. anonim yöntemler.)

using System;

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

    private static void CopyStrings(string[] source, string[] target, int startPos)
    {
        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 <= source.Length - 1; ctr++)
            target[ctr] = source[ctr];
    }
}

Aşağıdaki örnekte gösterildiği gibi bir lambda ifadesini Action<T1,T2,T3> temsilci örneğine de atayabilirsiniz. (Lambda ifadelerine giriş için bkz. Lambda İfadeleri (C#) veya Lambda İfadeleri (F#).)

using System;

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

    private static void CopyStrings(string[] source, string[] target, int startPos)
    {
        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 <= source.Length - 1; ctr++)
            target[ctr] = source[ctr];
    }
}

open System

let copyStrings (source: string []) (target: string []) startPos =
    if source.Length <> target.Length then
        raise (IndexOutOfRangeException "The source and target arrays must have the same number of elements.")

    for i = startPos to source.Length - 1 do
        target.[i] <- source.[i]

let ordinals = [| "First"; "Second"; "Third"; "Fourth"; "Fifth" |]
let copiedOrdinals: string [] = Array.zeroCreate ordinals.Length

let copyOperation = Action<_,_,_> (fun s1 s2 pos -> copyStrings s1 s2 pos)

copyOperation.Invoke(ordinals, copiedOrdinals, 3)

for ordinal in copiedOrdinals do
    printfn "%s" (if String.IsNullOrEmpty ordinal then "<None>" else ordinal)

Public Module TestLambda
    Public Sub RunIt()
        Dim ordinals() As String = {"First", "Second", "Third", "Fourth", "Fifth"}
        Dim copiedOrdinals(ordinals.Length - 1) As String
        Dim copyOperation As Action(Of String(), String(), Integer) =
                           Sub(s1, s2, pos) CopyStrings(s1, s2, pos)
        copyOperation(ordinals, copiedOrdinals, 3)
        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) 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 source.Length - 1
            target(ctr) = source(ctr)
        Next
        Return source.Length - startPos
    End Function
End Module

' The example displays the following output:
'       Fourth
'       Fifth

Uzantı Metotları

Şunlara uygulanır

Ayrıca bkz.

• Func<T1,T2,T3,TResult>