//Определить список товаров заданного поставщика
public List <Product> GetProductsByProvider(string providerName)
{
ProductGateWay productGateWay = new ProductGateWay(connString);
ProviderGateWay providerGateWay = new ProviderGateWay(connString);
Provider ourNeeded = providerGateWay.GetAll().First(x => x.Name == providerName);
return(productGateWay.GetAll().Where(x => x.ProviderId == ourNeeded.Id).ToList());
}
//Определить всех поставщиков товаров заданной категории
public List <Provider> GetProvidersByCategory(string categoryName)
{
ProviderGateWay providerGateWay = new ProviderGateWay(connString);
List <Provider> providers = new List <Provider>();
List <int> l1 = GetProductsByCategory(categoryName).Select(x => x.ProviderId).ToList();
List <Provider> l2 = providerGateWay.GetAll().ToList();
List <Provider> res = new List <Provider>();
foreach (Provider item in l2)
{
if (l1.Any(c => c == item.Id))
{
res.Add(item);
}
}
return(res);
}