Advanced

Trello.Advanced

It has four methods, Get, Post, Put and Delete. They all accept a uri and an object with additional arguments. The return type is either dynamic or a type of your choosing.

This is how you could make that request:

dynamic myList = trello.Advanced.Get("/lists/1234567890abcdefghijklmn", 
    new { cards = "all" });

Console.WriteLine(myList.name);

foreach (var card in myList.cards)
    Console.WriteLine(card.name);

You can also create your own type if you don't want to deal with dynamic:

public class MyList
{
    public string Name { get; set; }
    public IEnumerable<MyCard> Cards { get; set; }
}

public class MyCard
{
    public string Name { get; set; }
}

MyList myList = trello.Advanced.Get<MyList>("/lists/1234567890abcdefghijklmn", 
    new { cards = "all" });

Console.WriteLine(myList.Name);

foreach (var card in myList.Cards)
    Console.WriteLine(card.Name);

The trello api is documented here: https://trello.com/docs/index.html.