Array.ForEach<T>(T[], Action<T>) Method

Reference

Definition

Namespace:: System

Assemblies:: netstandard.dll, System.Runtime.dll

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Performs the specified action on each element of the specified array.

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))

Type Parameters

T

The type of the elements of the array.

Parameters

array: T[]

The one-dimensional, zero-based Array on whose elements the action is to be performed.

action: Action<T>

The Action<T> to perform on each element of array.

Exceptions

ArgumentNullException

array is null.

-or-

action is null.

Examples

The following example shows how to use ForEach to display the squares of each element in an integer array.

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

Remarks

The Action<T> is a delegate to a method that performs an action on the object passed to it. The elements of array are individually passed to the Action<T>.

This method is an O(n) operation, where n is the Length of array.

In F#, the Array.iter function can be used instead.

Applies to

Produit	Versions
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

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