Find all items in all sublist in

Question

I've an object list with a property that is sublist (object list)

public class Class2
{
    public String Item1 { get; set; }
    public int Item2 { get; set; }
}

public class Class1
{
    public String ItemA { get; set; }
    public List<Class2> Classes2 { get; set; }
}

List<Class1> classes1 = new List<Class1> ();

I would like to find all existing Class2.Item1 in classes1. Is it possible in linq c# ? thks

Answer 1

All distinct? However, you can use SelectMany:

var allDistinctItem1 = classes1.SelectMany(x => x.Classes2.Select(y => y.Item1)).Distinct();