ThenInclude not working for an Entity Framework LINQ query [duplicate]

Question

I have a database model like this:

public class Customer
{
    public int CustomerId{ get; set; }

    public int OrderId { get; set; }
    public ICollection<Order> Orders { get; set; }
}

public class Order
{
    public int OrderId { get; set; }
    public int Amount { get; set; }

    public int ProductId { get; set; }
    public Product Product { get; set; }
}

public class Product
{
    public int ProductId { get; set; }
    public string Name { get; set; }
}

So we have a customer which can do an order. This order includes a product and this includes a name. I'm now trying to return the complete model with a linq statement like the following:

_db.Customer.Include(c => c.Orders).ThenInclude(o => o.Product).SingleOrDefaultAsync();

But ThenInclude(o => o.Product) doesn't function because Orders is an ICollection. Greetings from Germany and thanks in advance for any help.

Answer 1

To load related entities in EF 6 you should use Select method as I show below:

_db.Customer.Include(c => c.Orders.Select(o=>o.Product)).SingleOrDefaultAsync();

ThenInclude method was added in EF Core, which is the last version of EF.