LINQ:查询集合中的集合

Question

我有以下结构:

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; }
}

我需要获得订购ProductID = 6的客户的集合.流畅的样式LINQ会是什么样的？

我试着下面没有运气:

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

Answer 1

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