在实体框架查询中创建嵌套列表

Question

问题描述：我正在将ASP.NET Core 2.1与Entity Framework Core一起使用来创建Web API。

我想重写我的Entity Framework查询，以将一个列表作为键的值而不是键/值对的列表输出。

预期结果：

{
    "insertedAt": "2019-10-17T17:03:55.813",
    "country": "Germany",
    "forecastRun": "56F1D5B4-F0EF-11E9-8522-04D3B088DC49",
    "origin": "manual",
    "id": 68,
    "Timeseries": [
        {
                "timestamp": "2019-10-14T19:00:00", "value": 12
        },
        {
                "timestamp": "2019-10-14T20:00:00", "value": 10
        },
        {
                "timestamp": "2019-10-14T21:00:00", "value": 19
        }
    ]
}

实际结果：

[
    {
        "value": 0,
        "insertedAt": "0001-01-01T00:00:00",
        "timestamp": "0001-01-01T00:00:00",
        "country": null,
        "forecastRun": null,
        "origin": null,
        "id": 68,
        "Timeseries": []
    },
    {
        "value": 0,
        "insertedAt": "0001-01-01T00:00:00",
        "timestamp": "0001-01-01T00:00:00",
        "country": null,
        "forecastRun": null,
        "origin": null,
        "id": 69,
        "Timeseries": []
    }
    ...
]

如您所见，它现在不仅可以输出键/值对的预期列表，而且还可以释放所有其他信息。

我尝试过的事情：

Models / ForecastModel.cs

using System;
using System.Collections.Generic;

namespace tradingdata.Models
{
    public partial class ModelForecast
    {
        public int Value { get; set; }
        public DateTime InsertedAt { get; set; }
        public DateTime Timestamp { get; set; }
        public string Country { get; set; }
        public string ForecastRun { get; set; }
        public string Origin { get; set; }
        public int Id { get; set; }
        public IEnumerable<Timeseries> MyTimestamps { get; set; }
        = new List<Timeseries>();
    }
    public partial class Timeseries
    {
        public int Id { get; set; }
        public double Value { get; set; }
        public DateTime Timestamp { get; set; }

    }
}

Controllers / ForecastController.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using tradingdata.Models;

namespace tradingdata.Controllers
{
    [Route("api/forecasts")]
    [ApiController]
    public class ForecastController : ControllerBase
    {
        private readonly tradingdataContext _context;

        public ForecastController(tradingdataContext context)
        {
            _context = context;
        }

        [HttpGet]
        public async Task<IActionResult> GetModelForecast([FromQuery] DateTime from, DateTime to, string model, string country)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            var forecasts = await _context.ModelForecast
                                                    .Where(m => m.Timestamp >= from && m.Timestamp <= to && m.Country == country)
                                                    .ToListAsync();

            if (forecasts == null)
            {
                return NotFound();
            }
            return Ok(forecasts.Select(x => new ModelForecast
            {
                Id = x.Id,
                MyTimestamps = x.MyTimestamps.Select(z => new Timeseries
                {
                    Id = z.Id
                })
            })
             );
        }


    }
}

感谢您的帮助。