Access included table properties in entity framework - asp.net-mvc

Question

I have two tables:
Table 1 (Sale):
Id | CustomerId
Table 2 (SaleProduct):
Id | SaleId | Quantity
I have the following statement:
var topSales = db.Sales.Include(c => c.SaleProducts).Where(p =>p.CustomerId == id);
I want to sort the SaleProducts table, and select 5 top(ordered by quantity) based on SaleId foreign key, where CustomerId is equal with an id it receives in a controller method.
How can I access the SaleProducts properties in order to do something like this:
var orderedItems = topSales.OrderByDescending(c => c.Quantity).Take(5);
When I include the SaleProducts table I have in there all the properties but I can't accesc them like in the statement above.
Any help is appreciated

Answer 1

You have two options here:
First option.
Try querying SaleProduct table instead of Sale table and Include Sale:
var topSaleProducts = db.SaleProducts
.Where(m => m.Sale.CustomerId == id)
.Include(m => m.Sale)
.OrderByDescending(m => m.Quantity)
.Take(5);
Now you have top 5 sale products according to CustomerId and Sale will alse be loaded.
Second option.
You can use explicit loading to get top 5 SaleProducts after loading Sale. Remember that, you will query database twice by this way:
// Load the sale first
var topSale = db.Sales.First(m => m.CustomerId == id);
// Then load SaleProducts using Explicit loading.
db.Entry(topSale)
.Collection(m => m.SaleProducts)
.Query()
.OrderByDescending(m => m.Quantity)
.Take(5)
.Load();

Answer 2

You can order by when you access the SaleProducts property and use Take method to get 5 items.
var prods2 = db.Sales.Include(c => c.SaleProducts)
.Where(p =>p.CustomerId == id)
.Select(g => new
{
SaleId = g.Id,
Products = g.SaleProducts.OrderByDescending(h => h.Quantity)
.Take(5)
.Select(x => new
{
Id = x.Id,
Quantity = x.Quantity
})
}).ToList();
The above code will give you the Sales for a specific customer and for each customer it will include only the top 5 SaleProduct's (sorted by quantity)
I am projecting the results to an anonymous object ( new { }). If you have a view model, you can change the projection to that.
public class SaleVm
{
public int Id { set; get; }
public int CustomerId { set; get; }
public List<SaleProductVm> SaleProducts { set; get; }
}
public class SaleProductVm
{
public int Id { set; get; }
public int SaleId { set; get; }
public int Quantity { set; get; }
}
Simply replace the annonymous object projection with these classes
List<SaleVm> prods2 = db.Sales.Include(c => c.SaleProducts)
.Where(p =>p.CustomerId == id)
.Select(g => new SaleVm
{
SaleId = g.Id,
Products = g.SaleProducts.OrderByDescending(h => h.Quantity)
.Take(5)
.Select(x => new SaleProductVm
{
Id = x.Id,
Quantity = x.Quantity
})
}).ToList();