如何使用泛型類型參數獲取類的所有屬性

Question

請參閱以下示例。 當具有屬性類型是具有泛型類型參數的類的屬性時，如何列出所有這些屬性而不管泛型類型參數？

class Program
{
    public static VehicleCollection<Motorcycle> MotorcycleCollection { get; set; }
    public static VehicleCollection<Car> CarCollection { get; set; }
    public static VehicleCollection<Bus> BusCollection { get; set; }

    static void Main(string[] args)
    {
        MotorcycleCollection = new VehicleCollection<Motorcycle>();
        CarCollection = new VehicleCollection<Car>();
        BusCollection = new VehicleCollection<Bus>();

        var allProperties = typeof(Program).GetProperties().ToList();
        Console.WriteLine(allProperties.Count);  // Returns "3".
        var vehicleProperties = typeof(Program).GetProperties().Where(p => 
            p.PropertyType == typeof(VehicleCollection<Vehicle>)).ToList();
        Console.WriteLine(vehicleProperties.Count);  // Returns "0".
        Console.ReadLine();
    }
}

public class VehicleCollection<T> where T : Vehicle
{
    List<T> Vehicles { get; } = new List<T>();
}

public abstract class Vehicle
{
}

public class Motorcycle : Vehicle
{
}

public class Car : Vehicle
{
}

public class Bus : Vehicle
{
}

Answer 1

您可以使用GetGenericTypeDefinition方法獲取泛型類型的開放形式，然后將其與VehicleCollection<> （打開表單）進行比較，如下所示：

var vehicleProperties = typeof(Program).GetProperties()
    .Where(p =>
        p.PropertyType.IsGenericType &&
        p.PropertyType.GetGenericTypeDefinition() == typeof(VehicleCollection<>))
    .ToList();

IsGenericType用於確保屬性類型是通用的。