c# - Entity Framework 核心: unhandled exception

Question

我正在尝试查询应用程序中的以下实体:

public class Reservation
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int ReservationId { get; set; }

    public int PersonId { get; set; }

    [ForeignKey("PersonId")]
    public Person Person { get; set; }

    [ForeignKey("FilmShowId")]
    public FilmShow FilmShow { get; set; }

    public int FilmShowId { get; set; }
}

public class Person
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int  PersonId { get; set; }

    [Required]
    [MaxLength(255)]
    public string FirstName { get; set; }

    [Required]
    [MaxLength(255)]
    public string LastName { get; set; }

    public string Email { get; set; }

    public ICollection<Reservation> Reservations = 
        new List<Reservation>();
}

我正在使用此查询:

public async Task<IEnumerable<Person>> GetPersonsAndReservations()
{
    return await _context.Persons.Include(p => p.Reservations).ToListAsync();
}

我不断收到以下异常:

ArgumentException: The Include property lambda expression 'p => p.Reservations' is invalid. The expression should represent a property access: 't => t.MyProperty'. To target navigations declared on derived types, specify an explicitly typed lambda parameter of the target type, E.g. '(Derived d) => d.MyProperty'.

我在这里做错了什么吗？

Answer 1

Person.Reservations 是一个字段，而 EF Core(尽管可以使用支持字段来实现)convention仅映射属性:

By convention, public properties with a getter and a setter will be included in the model.

简单地改变

public ICollection<Reservation> Reservations =
    new List<Reservation>();

至

public ICollection<Reservation> Reservations { get; set; } =
    new List<Reservation>();

问题应该得到解决。