c# – 2个参数中的一个返回null

我正在使用MVC.当我运行调试器并使用Postman进行测试并将鼠标悬停在参数上时,它显示参数传递给MovieIds的空值,但CustomerId正在按预期工作.

Api Controller:newRental在调试时将MovieIds显示为null

public class NewRentalsController : ApiController
{
    private ApplicationDbContext _context;

    public NewRentalsController()
    {
        _context = new ApplicationDbContext();
    }

    [HttpPost]
    public IHttpActionResult CreateNewRentals(NewRentalDto newRental)
    {
        var customer = _context.Customers.Single(c => c.Id == newRental.CustomerId);

        var movies = _context.Movies.Where(m => newRental.MovieIds.Contains(m.Id)).ToList();

        //var movies = _context.Movies.Where(m => m.Id ==1);

        foreach (var movie in movies)
        {
            if (movie.NumberAvailable == 0)
                return BadRequest("Movie is not available.");

            movie.NumberAvailable--;

            var rental = new Rental
            {
                Customer = customer,
                Movie = movie,
                DateRented = DateTime.Now
            };

            _context.Rentals.Add(rental);
        }

        _context.SaveChanges();

        return Ok();
    }

}

DTO:

public class NewRentalDto
{
    public int CustomerId { get; set; }
    public List<int> MovieIds { get; set; }
}

邮差要求:

{"customerId": 2,
"movieId": 1,
"dateRented": "2017-09-28T00:00:00"
}

我认为这与List< int>有关.因为我可以硬编码Id,它会将它发送到数据库.

最佳答案 正如你猜测的那样,问题是MovieIds是一个List< int>所以你的请求应该是这样的(使用方括号[]):

MovieIds: [1],
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