public static void GetCustomersInCategory(string name)
{
IEnumerable <Customer> customers = CustomerDb.GetAllCustomers();
IEnumerable <Category> categories = CategoryDb.GetAllCategories();
IEnumerable <CustomersGoods> customerGoodsDbs = CustomerGoodsDb.GetCustomerGoods();
var listOfCategories = categories.Where(p => p.Name == name);
var needProducts = listOfCategories.Join(customerGoodsDbs,
c => c.Product.IdGoods, cg => cg.Product.IdGoods, (c, cg) => new { Id = cg.Customer.IdCustomer });
var result = needProducts.Join(customers, arg => arg.Id, c => c.IdCustomer,
(arg, c) => new { Name = c.Name });
}
public static void GetCustomerWithMostCategories()
{
var customersHasGoods = CustomerGoodsDb.GetCustomerGoods();
var categories = CategoryDb.GetAllCategories();
var subresult = customersHasGoods.Join(
categories,
cg => cg.Product.IdGoods,
category => category.Product.IdGoods,
(cg, category) => new { Category = category, Customer = cg.Customer, Goods = category.Product });
var preres = subresult.GroupBy(r => r.Customer.Surname).Select(g => new { Name = g.Key, Count = g.Count() });
var res = preres.OrderByDescending(n => n.Count).First();
Console.WriteLine("Максимально разнообразный {0} - у него товары в {1} категориях", res.Name, res.Count);
}