array.convertall

//Double each value in an array using Array.ConvertAll();

using System;
public class Kata
{
  public static int[] DoubleTheArrayElements(int[] arr)
  {
    return Array.ConvertAll(arr, element => element * 2);
  } 
}

// could also just be done with LINQ like this:
return arr.Select(x => x * 2);
Albert Rovsing