我必须通过 LINQ 完成的代码

Question

我有一段代码，我必须通过 LINQ 来完成它

var airlineNameList = new List<string>();

foreach (DTTrip trip in contract_.Trips)
{
    foreach (DTFlight flight in trip.ListOfFlights)
    {
        airlineNameList.Add(flight.AirLineName);
    }
}

如何通过 LINQ 来完成它。 注意：contract_是类的对象。

请帮忙..

Answer 1

var airlineNameList = contract_.Trips
                               .SelectMany(t => t.ListOfFlights)
                               .Select(f => f.AirLineName);

Answer 2

var resultList = contract_.Trips
      .Cast<DTTrip>()
      .SelectMany(trip => trip.ListOfFlights.Cast<DTFlight>())
      .Select(flight => flight.AirLineName)
      .ToList();

难道你不需要Distinct吗？

Answer 3

var airlineNameList = (
    from trip in contract_.Trips
    from flight in trip.ListOfFlights
    select flight.AirLineName)
    .ToList();

C# foreach 会为你进行隐式转换（这很恶心），所以也许你需要这个：

var airlineNameList = (
    from trip in contract_.Trips.Cast<DTTrip>()
    from flight in trip.ListOfFlights.Cast<DTFlight>()
    select flight.AirLineName)
    .ToList();