using System;

using System.Collections;

using System.Collections.Generic;

using System.Globalization;

using System.Linq;

using System.Reflection;

​

using KGySoft.CoreLibraries;

​

public class Program

{

    public static void Main()

    {

        var strings = new List<List<List<string>>>{new(){new() {"1", "2", "3"}, new() {"4", "5", "6"}}};

        var ints = strings.Convert<List<List<List<int>>>>();

        Console.WriteLine($"To {ints.GetType().GetName(TypeNameKind.ShortName)} result: {Dump(ints)}");

    }

​

    private static string Dump(object o)

    {

        if (o == null)

            return "<null>";

        var convertible = o as IConvertible;

        if (convertible != null)

            return convertible.ToString(CultureInfo.InvariantCulture);

        var enumerable = o as IEnumerable;

        if (enumerable != null)

            return $"[{enumerable.Cast<object>().Select(Dump).Join(", ")}]";

        return $"{{{o.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance).Select(p => $"{p.Name} = {Dump(p.GetValue(o))}").Join(", ")}}}";

    }

}