How do you loop through a multidimensional array?

Question

foreach (String s in arrayOfMessages)
{
    System.Console.WriteLine(s);
}

string[,] arrayOfMessages is being passed in as a parameter

Answer 1

It looks like you found an answer suitable for your problem, but since the title asks for a multidimensional array (which I read as 2 or more), and this is the first search result I got when searching for that, I'll add my solution:

public static class MultidimensionalArrayExtensions
{
    /// 

    /// Projects each element of a sequence into a new form by incorporating the element's index.
    /// 
    /// The type of the elements of the array.
    /// A sequence of values to invoke the action on.
    /// An action to apply to each source element; the second parameter of the function represents the index of the source element.
    public static void ForEach(this Array array, Action action)
    {
        var dimensionSizes = Enumerable.Range(0, array.Rank).Select(i => array.GetLength(i)).ToArray();
        ArrayForEach(dimensionSizes, action, new int[] { }, array);
    }
    private static void ArrayForEach(int[] dimensionSizes, Action action, int[] externalCoordinates, Array masterArray)
    {
        if (dimensionSizes.Length == 1)
            for (int i = 0; i < dimensionSizes[0]; i++)
            {
                var globalCoordinates = externalCoordinates.Concat(new[] { i }).ToArray();
                var value = (T)masterArray.GetValue(globalCoordinates);
                action(value, globalCoordinates);
            }
        else
            for (int i = 0; i < dimensionSizes[0]; i++)
                ArrayForEach(dimensionSizes.Skip(1).ToArray(), action, externalCoordinates.Concat(new[] { i }).ToArray(), masterArray);
    }

    public static void PopulateArray(this Array array, Func calculateElement)
    {
        array.ForEach((element, indexArray) => array.SetValue(calculateElement(indexArray), indexArray));
    }
}

Usage example:

var foo = new string[,] { { "a", "b" }, { "c", "d" } };
foo.ForEach((value, coords) => Console.WriteLine("(" + String.Join(", ", coords) + $")={value}"));
// outputs:
// (0, 0)=a
// (0, 1)=b
// (1, 0)=c
// (1, 1)=d

// Gives a 10d array where each element equals the sum of its coordinates:
var bar = new int[4, 4, 4, 5, 6, 5, 4, 4, 4, 5];
bar.PopulateArray(coords => coords.Sum());

General idea is to recurse down through dimensions. I'm sure the functions won't win efficiency awards, but it works as a one-off initialiser for my lattice and comes with a nice-enough ForEach that exposes the values and indices. Main downside I haven't solved is getting it to automatically recognise T from the Array, so some caution is required when it comes to the type safety.