Build a datatable from other datatables

Such a thing can help you, you can change the string object to any object you need and use the operative you need to implement within the second for:

    public static List<string> gComb(List<List<string>> list)
    {
        List<string> res = new List<string>();
        List<string> first = list.First();
        List<List<string>> aux = list.Skip(1).ToList();

        if (list.Count > 1)
        {
            foreach (string s in gComb(aux))
            {
                foreach (string st in first)
                {
                    res.Add(st + ", " + s);
                }
            }
            return res;
        }
        else {
            return list.First();
        }
    }

Use linQ and recursion.

Although the question itself does not show much effort, I will try to give an answer because I think the topic is interesting.

What you are looking for in mathematics is called Cartesian Product and in SQL Cross Join, and being known the number of tables is Simple to solve using linq:

var producto = 
from primero in s1 
from segundo in s2 
from tercero in s3 
select new[] {first, second, third};

This makes the Cartesian product of 3 IEnumerables .

When the ticket listing number is unknown, things get complicated but through Linq it is also possible to do so. I add an example below that makes use of an extension method to make the Cartesian product of an unknown number of, in this example, arrays:

Extension method

public static IEnumerable<IEnumerable<T>> ProductoCartesiano<T>(this IEnumerable<IEnumerable<T>> secuencias)
{
    IEnumerable<IEnumerable<T>> result = new[] { Enumerable.Empty<T>() };
    foreach (var secuencia in secuencias)
    {
        var s = secuencia; 
        // usando SelectMany
        resultado = resultado.SelectMany(s1 => s, (s1, s2) => (s1.Concat(new[] { s2 }))).ToArray(); //lambda

        //Usando Linq
        //resultado =
        //from seq in resultado
        //from item in s
        //select secuencia.Concat(new[] { item }).ToArray();
    }
    return resultado;
}

Example

string[] data1 = new string[2] { "a1", "a2" };
string[] data2 = new string[3] { "b1", "b2", "b3" };
string[] data3 = new string[2] { "c1", "c2" };

List<string[]> listaDatos = new List<string[]>();
listaDatos.Add(data1);
listaDatos.Add(data2);
listaDatos.Add(data3);

var productoCartesiano = listaDatos.ProductoCartesiano().Select(x=>String.Join(",",x)).ToList();

To finish, I do not want to attribute the merit of this solution, I have only adapted the code a bit. The brain is Mr. Eric Lippert and he explains it perfectly in your MSDN Blog