LINQ: Query a collection within a collection

I have following structure:

开发者_JAVA百科public class Customer
{
  public int ID { get; set; }
  public List<Order> Orders { get; set; }
}

public class Order
{
  public int ID { get; set; }
  public int ProductID { get set; }
}

I need to get the collection of customers that ordered ProductID = 6. What would the fluent style LINQ look like?

I tried below with no luck:

var customers = allCustomers.SelectMany(c => c.Orders.Select(o => o.ProductID.Equals(6))).ToArray();

var customers = allCustomers.Where(c => c.Orders.Any(o => o.ProductID == 6));

allCustomers.Where(c => c.Orders.Any(o => o.ProductID == 6))

var customers = allCustomers.Where(c => c.Orders.Any(o => o.ProductID == 6));

Looks like you want:

var query = allCustomers.Where(c => c.Orders.Any(o => o.ProductID == 6));

A nice way would be to try from the other side like this

var customers from p in Order where p.ProductId == 6 select p.Customer

And of course you need the add the Customer property in the Order class like this

public class Order
{
  public int ID { get; set; }
  public int ProductID { get set; }
  public Customer Customer { get; set; }
}