Flatten a list which one of its properties is another list of object

Question

I have the following classes:

public class Owner
{
    public string Id { get; set; }
    public string Name { get; set; }
}
public class Main
{
    public s         


        

Answer 1

List
 mainList = ...
var flatList = (
    from main in mainList
    from owner in main.Owners
    select new FlatList {
        Id = main.Id, Name = main.Name,
        OwnerId = owner.Id, OwnerName = owner.Name
    }).ToList();