在动作结果之间传递模型时丢失属性值

Question

我是MVC的初学者和新手。我目前正在进行一个演示项目，我很难继续。这是我项目的模型：

public class Deliveries
{
    [Key]
    public int Id { get; set; }
   // public Boolean Checkbox { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Street { get; set; }
    public int StreetNumber { get; set; }
    public int Zipcode { get; set; }
    public string City { get; set; }
    [DataType(DataType.Date)]
    [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}")]
    public DateTime Date { get; set; }
    public TimeSpan Time { get; set; }
    public string Details { get; set; }

}

public class Tours
{   
    [Key]
    public virtual int Id { get; set; }
    public virtual string Name { get; set; }
    public virtual List<int> DeliveriesIds { get; set; }
    public virtual List<Deliveries> Deliveries { get; set; }


}

我创建了交付并选择了一对ViewModel：

public class SelectedDeliveriesEditorViewModel
{
    public bool Selected { get; set; }
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Street { get; set; }
    public int StreetNumber { get; set; }
    public int Zipcode { get; set; }
    public string City { get; set; }
    [DataType(DataType.Date)]
    [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}")]
    public DateTime Date { get; set; }
    public TimeSpan Time { get; set; }
    public string Details { get; set; }


}

public class SelectedDeliveriesWrapperViewModel
{
    public List<SelectedDeliveriesEditorViewModel> SelectedDeliveries { get; set; }
    public SelectedDeliveriesWrapperViewModel()
    {
        this.SelectedDeliveries = new List<SelectedDeliveriesEditorViewModel>();
    }
    public string TourName { get; set; }
    public List<int> getSelectedIds()
    {
        return (from t in this.SelectedDeliveries where t.Selected select t.Id).ToList();
    }
}

最后，我想将选定的交付显示为巡视。这是我的ToursController：

public class ToursController : Controller
{
    DeliveriesManagerDb _db = new DeliveriesManagerDb();

    //
    // GET: /Tours/

    public ActionResult Index()
    {
        var model = new SelectedDeliveriesWrapperViewModel();
        foreach(var delivery in _db.Deliveries)
        {
            var editorViewModel = new SelectedDeliveriesEditorViewModel
            {
                Id = delivery.Id,
                FirstName = delivery.FirstName,
                LastName = delivery.LastName,
                Street = delivery.Street,
                StreetNumber = delivery.StreetNumber,
                Zipcode = delivery.Zipcode,
                City = delivery.City,
                Date = delivery.Date,
                Time = delivery.Time,
                Details = delivery.Details,
                Selected = false
            };
            model.SelectedDeliveries.Add(editorViewModel);
        }
        return View(model);

    }

    //
    // POST: /Tours/SubmitSelected

    [HttpPost]
    public ActionResult SubmitSelected(SelectedDeliveriesWrapperViewModel model)
    {


        var selectedIds = model.getSelectedIds();

        Tours tour = new Tours();

        tour.Name = model.TourName;
        tour.Deliveries = _db.Deliveries.ToList();
        tour.DeliveriesIds = selectedIds.ToList();



        _db.Tours.Add(tour);
        _db.SaveChanges();



        return RedirectToAction("TourManagement", "Tours", new { id = tour.Id });
    }
    [HttpGet]
    public ActionResult TourManagement(int id)
    {
        Tours tour = _db.Tours.Find(id);
        if (tour == null)
        {
            return HttpNotFound();
        }

        return View(tour);
    }
}

当我在ActionResult TourManagemnt中调用View时，我收到NullException错误。当我调试时，我在ActionResult SubmitSelected中看到DeliveriesIds的值，但是当它将它们传递给TourManagement操作时，我将丢失列表为空，只有Tour的名称和所有交付的集合都存在。

对于这篇长篇文章感到抱歉，非常感谢任何帮助。