属性个反序列化 JSON 个对象仅在存储库 class 中始终为 null

Question

我的控制器中有一个简单的 GET 函数，用于 return 我存储库中的一小部分对象。每个对象的其中一个属性仅在存储库 class 中始终为空，但在最初填充时不是 dbcontext 本身。我只是为此使用 InMemoryDatabase。

这是我的 Home.cs 模型 class:

public class Home
{
    public int Id { get; set; }

    [Required(ErrorMessage = "Address is required")]
    public Address Address { get; set; } // this is what is null

    [Required(ErrorMessage = "Number of rooms is required")]
    public int NumRooms { get; set; }

    [Range(1, 5, ErrorMessage = "Must give a rating between 1 and 5")]
    public int Rating { get; set; }
}

这是 Address.cs 模型：

public class Address
{
    public int Id { get; set; }

    [Required(ErrorMessage = "City is required")]
    public string City { get; set; }

    [Required(ErrorMessage = "State is required")]
    public string State { get; set; }

    [Required(ErrorMessage = "ZipCode is required")]
    [StringLength(5, MinimumLength = 5)]
    public string ZipCode { get; set; }
}

这是我在 Program.cs 中的 Main 函数，我在其中调用以生成一些数据：

public class Program
{
    public static void Main(string[] args)
    {
        var host = CreateHostBuilder(args).Build();
        using (var scope = host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;
            var context = services.GetRequiredService<RepositoryContext>();

            DataGenerator.SeedData(context);
        }
        host.Run();
    }

    // rest of Program.cs
}

这是 DataGenerator class:

public class DataGenerator
{
    public static void SeedData(RepositoryContext context)
    {
        if (!context.Homes.Any())
        {
            var homeData = System.IO.File.ReadAllText("Data/Homes.json");
            var homes = JsonConvert.DeserializeObject<List<Home>>(homeData);
            context.AddRange(homes);
            context.SaveChanges();
        } // I verify here that the home objects in context DO have valid Addresses
    }
}

这里是 Homes.json:

[
  {
    "Address": {
      "City": "CityOne",
      "State": "MA",
      "ZipCode": "44444"
    },
    "NumRooms": "4",
    "Rating": "4"
  },
  {
    "Address": {
      "City": "CityTwo",
      "State": "MA",
      "ZipCode": "3333"
    },
    "NumRooms": "3",
    "Rating": "3"
  },
  {
    "Address": {
      "City": "AnotherCity",
      "State": "MA",
      "ZipCode": "22222"
    },
    "NumRooms": "2",
    "Rating": "2"
  },
  {
    "Address": {
      "City": "SomeCity",
      "State": "MA",
      "ZipCode": "11111"
    },
    "NumRooms": "1",
    "Rating": "1"
  }
]

这是 Dbcontext class:

public class RepositoryContext : DbContext
{
    public DbSet<Home> Homes{ get; set; }

    public RepositoryContext(DbContextOptions<RepositoryContext> options) : base(options)
    {
    }
}

这是 Startup.cs ConfigureServices 函数中的相关位：

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<RepositoryContext>(x => x.UseInMemoryDatabase("Homes"));
    services.AddScoped<IHomeRepository, HomeRepository>();
    // rest of function
}

HomeRepository class:

public class HomeRepository : IHomeRepository
{
    private readonly RepositoryContext _context;

    public HomeRepository(RepositoryContext context)
    {
        _context = context; // context shows addresses as null here
    }

    public async Task<IEnumerable<Home>> GetHomes()
    {
        var homes = await _context.Homes.ToListAsync(); // address is null here for all home objects
        return homes;
    }
}

最后，这是相关的控制器class：

[ApiController]
[Route("api/[controller]")]
public class HomeController : ControllerBase
{
    private readonly IHomeRepository _repository;

    public HomeController(IHomeRepository repository)
    {
        _repository = repository;
    }

    [HttpGet]
    public async Task<IActionResult> GetHomes()
    {
        var homes = await _repository.GetHomes(); // address is null here for all objects
        return Ok(homes);
    }
}

Answer 1

忘记包含 Address 实体。这就是address没有出现的原因。
将.Include(h=>h.Address)添加到Homes。

    public async Task<IEnumerable<Home>> GetHomes()
    {
        //var homes = await _context.Homes.ToListAsync(); // address is null here for all home objects
        
        var homes = await _context.Homes.Include(h=>h.Address).ToListAsync(); // include address table

        return homes;
    }

Screenshot

有效。

顺便说一句，这是我见过最详细的问题。 :D

属性个反序列化 JSON 个对象仅在存储库 class 中始终为 null

Property of deserialized JSON objects are always null only in repository class

json

dbcontext

asp.net-core-webapi

属性 个反序列化 JSON 个对象仅在存储库 class 中始终为 null

Property of deserialized JSON objects are always null only in repository class

json

dbcontext

asp.net-core-webapi

属性个反序列化 JSON 个对象仅在存储库 class 中始终为 null