Design and Architecture

public class Customer
{
    public List<Order> Orders { get; set; }
}

public class Order
{
    public Customer Customer { get; set; }
    public List<OrderLine> Lines { get; set; }
}

public class Product
{
    public List<OrderLines> OrderLines { get; set; }
}

public class OrderLine
{
    public Order Order { get; set; }
    public Product Product { get; set; }
}

Richard Deeming wrote:

I'd be inclined to have a shared class library of DTOs used to communicate with the API, and put the validation in there.

Gerry Schmitz wrote:

I could produce some "video evidence"