Eager loading nested entities

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0

I have the following (kept really simple):

public class Customer
{
    public int Id {get; set}
    public IEnumerable<Reminder> Reminders {get; set}
    public IEnumerable<Order> Orders {get; set}
}

public class Reminder
{
    public int CustomerId {get; set}
    public string Text {get; set}
}

public class Order
{
    public int CustomerId {get; set}
    public int CategoryId {get; set}
}

public class OrderDetails
{
    public int OrderId {get; set}
    public int ProductId {get; set}
}

I'm also using generic repository pattern, and I load entities with nested entities as follows:

    public virtual T Get(int id, params Expression<Func<T, object>>[] include)
    {
        if (include.Any())
        {
            var set = include.Aggregate<Expression<Func<T, object>>, IQueryable<T>>
                        (dbset, (current, expression) => current.Include(expression));

            return set.SingleOrDefault<T>(x => x.Id == id);
        }

        return dbset.Find(id);
    }

Using Linq, I would like to load a Customer, all his Reminders and all Orders having a particular CategoryId. So I'm trying to do like this:

var customer = customerRepository.Get(10, x => x.Reminders, x => x.Orders.Select(o => o.OrderDetails));

But the above loads everything. And if I do the following, an exception is thrown:

var customer = customerRepository.Get(10, x => x.Reminders, x => x.Orders.Where(c => c.CategoryId == categoryId).Select(o => o.OrderDetials));

So how can I actually return only those orders I need?

asked 2 mins ago

Ivan-Mark Debono

398

Eager loading nested entities