c# - 如何使用泛型类型参数获取类的所有属性

Question

请参阅以下示例。当具有属性类型是具有泛型类型参数的类的属性时，无论泛型类型参数如何，如何列出所有这些属性？

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

您可以使用该GetGenericTypeDefinition方法获取泛型类型的开放形式，然后将其与VehicleCollection<>（开放形式）进行比较，如下所示：

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

IsGenericType用于确保属性类型是通用的。