C # arrayList of Objects

When adding the "data" objects to the ArrayList, to be able to consult them later, you have to access the ArrayList.

According to your code, in the first position of aL, you have one data object and in the second one another.

To get the first aL object, you have to do the following:

String[,] dato1 = aL[0]; //Como si fuese un array

Once you have obtained the element, to access its properties it is very simple.

string nombre = dato1[0][0];  //Esto debería devolver Juan

If you would like to obtain all the data of your list you can do it like this:

for(int i=0; i<aL.Count; i++)
{
    string[,] dato = aL[i]; //Cada iteración del bucle tendremos un elemento del listado
}

I can not stand the curiosity to see how to solve this in the terms and this is the result:.

  ArrayList aL = new ArrayList();
        String[,] datos = new String[1, 2];
        datos[0, 0] = "Juan";
        datos[0, 1] = "1258";
        aL.Insert(0, datos); // Inserta el Array en la posicion 0 del ArrayList

        String[,] datos2 = new String[1, 2];
        datos2[0, 0] = "Pedro";
        datos2[0, 1] = "2684";
        aL.Insert(1,datos2); // Inserta el Array en la posicion 1 del ArrayList

        for (int i = 0; i < aL.Count; i++)
        {
            string[,] ArrayEnArrayList = (System.String[,])aL[i];
            System.Console.WriteLine("Elemento del ArrayList: " + i.ToString());

            int numeroDeFilas = ArrayEnArrayList.GetLength(0);
            int numeroDeColumnas = ArrayEnArrayList.GetLength(1);

            for (int f = 0; f < numeroDeFilas; ++f)
            {
                for (int c = 0; c < numeroDeColumnas; ++c)
                {
                    Console.WriteLine(ArrayEnArrayList[f,c]);
                }
            }
        }
        System.Console.ReadLine();

The first thing you are using Matrices, as we do not know how to use it, I recommend you better Vectors. Also better to use List. There goes:

List<string[]> lista = new List<string[]>();
lista.Add(new string[] { "Juan", "1258" });
lista.Add(new string[] { "Pedro", "2684" });

//Si quieres recuperar una posición en concreto..
string[] juan = lista[0];
//Si prefieres recuperar por nombre.. por ejemplo Pedro
string[] pedro = lista.Find(find => find[0].Equals("Pedro"));