public CityCollection()
{
Cities = new List <City>();
DistrictCollection districtCollection = new DistrictCollection();
this.Cities.Add(new City(111, "Витебск", districtCollection.Districts.Find(d => d.DistrictCode == 11)));
this.Cities.Add(new City(112, "Брест", districtCollection.Districts.Find(d => d.DistrictCode == 11)));
this.Cities.Add(new City(311, "Сидней", districtCollection.Districts.Find(d => d.DistrictCode == 31)));
this.Cities.Add(new City(411, "Мельбурн", districtCollection.Districts.Find(d => d.DistrictCode == 41)));
}
static void Main(string[] args)
{
List <Country> cc = new CountryCollection().Countries;
List <District> dc = new DistrictCollection().Districts;
List <City> ctc = new CityCollection().Cities;
List <Neighborhood> nbc = new NeighborhoodCollection().Neighborhoods;
var results = from country in cc
join d in dc on country.CountryCode equals d.Country.CountryCode
join ct in ctc on d.DistrictCode equals ct.District.DistrictCode
join nb in nbc on ct.CityCode equals nb.City.CityCode
select new { nb.StreetName };
foreach (var result in results)
{
Console.WriteLine($"street: {result.StreetName}");
}
Console.ReadKey();
}