Array.ForEach<T>(T[], Action<T>) 方法

定義

命名空間:

System

組件:

System.Runtime.dll

來源:

Array.cs

在指定之陣列的每一個項目上執行指定之動作。

public:
generic <typename T>
 static void ForEach(cli::array <T> ^ array, Action<T> ^ action);

public static void ForEach<T> (T[] array, Action<T> action);

static member ForEach : 'T[] * Action<'T> -> unit

Public Shared Sub ForEach(Of T) (array As T(), action As Action(Of T))

類型參數

T

陣列項目的類型。

參數

array

T[]

以零為起始的一維 Array，要在其項目上執行動作。

action

Action<T>

要在 array 的每一個項目上執行的 Action<T>。

例外狀況

ArgumentNullException

array 為 null。

-或-

action 為 null。

範例

下列範例示範如何使用 ForEach 來顯示整數陣列中每個專案的平方。

using namespace System;

public ref class SamplesArray
{
public:
    static void Main()
    {
        // create a three element array of integers
        array<int>^ intArray = gcnew array<int> {2, 3, 4};

        // set a delegate for the ShowSquares method
        Action<int>^ action = gcnew Action<int>(ShowSquares);

        Array::ForEach(intArray, action);
    }

private:
    static void ShowSquares(int val)
    {
        Console::WriteLine("{0:d} squared = {1:d}", val, val*val);
    }
};

int main()
{
    SamplesArray::Main();
}

/*
This code produces the following output:

2 squared = 4
3 squared = 9
4 squared = 16
*/

using System;

public class SamplesArray
{
    public static void Main()
    {
        // create a three element array of integers
        int[] intArray = new int[] {2, 3, 4};

        // set a delegate for the ShowSquares method
        Action<int> action = new Action<int>(ShowSquares);

        Array.ForEach(intArray, action);
    }

    private static void ShowSquares(int val)
    {
        Console.WriteLine("{0:d} squared = {1:d}", val, val*val);
    }
}

/*
This code produces the following output:

2 squared = 4
3 squared = 9
4 squared = 16
*/

open System

let showSquares val' =
    printfn $"%i{val'} squared = %i{val' * val'}"

// create a three element array of integers
let intArray = [| 2..4 |]

Array.ForEach(intArray, showSquares)
// Array.iter showSquares intArray

// This code produces the following output:
//     2 squared = 4
//     3 squared = 9
//     4 squared = 16

Public Class SamplesArray
    Public Shared Sub Main()
        ' create a three element array of integers
        Dim intArray() As Integer = New Integer() {2, 3, 4}

        ' set a delegate for the ShowSquares method
        Dim action As New Action(Of Integer)(AddressOf ShowSquares)

        Array.ForEach(intArray, action)
    End Sub

    Private Shared Sub ShowSquares(val As Integer)
        Console.WriteLine("{0:d} squared = {1:d}", val, val*val)
    End Sub
End Class

' This code produces the following output:
'
' 2 squared = 4
' 3 squared = 9
' 4 squared = 16

備註

Action<T>是方法的委派，它會對傳遞給它的物件執行動作。 的專案 array 會個別傳遞至 Action<T> 。

這個方法是 O (n) 作業，其中 n 是 Length 的 array 。

在 F# 中，可以改用 Array.iter 函 式。

另請參閱

• Action<T>