模型值为空

我有以下型号:

[HttpPost("/case")]
public async Task<IActionResult> CreateCase([FromBody] Case model)
{
    if (!ModelState.IsValid)
        return BadRequest();

    _context.Cases.Add(model);
    await _context.SaveChangesAsync();

    return Success(model);
}

但是,当它到达 model 所有值都设置为 null

有人能告诉我我做错了什么吗?

更新

当我试图删除它以便我的请求如下所示:

同样的事情发生了

案例

    namespace API.Models
{
    public class Case
    {
        public long Id { get; set; }

        public string Name { get; set; }
        public string Description { get; set; }

        public int Size { get; set; }

        public long BuildingTypeId { get; set; }
        public BuildingType BuildingType { get; set; }

        public long BuildingPurposeId { get; set; }
        public BuildingPurpose BuildingPurpose { get; set; }

        public long ApplicationUserId { get; set; }
        public ApplicationUser ApplicationUser { get; set; }

        public long LocationId { get; set; }
        public Location Location { get; set; }

        public long FireStrategyId { get; set; }
        public FireStrategy FireStrategy { get; set; }

        public List<CaseMaterial> Materials { get; set; }

        public List<Installation> Installations { get; set; }

        public List<DocumentationFile> Files { get; set; }
    }
}