ASP .net MVC 列表未更新

>我在类中设置了列表，该列表已初始化并在主构造函数中添加了 1 个项目，但由于某种原因，从创建视图添加它不会将其添加到列表中。任何帮助将不胜感激。

public class PhoneBase
{
    public PhoneBase()
    {
        DateReleased = DateTime.Now;
        PhoneName = string.Empty;
        Manufacturer = string.Empty;
    }
    public int Id { get; set; }
    public string PhoneName { get; set; }
    public string Manufacturer { get; set; }
    public DateTime DateReleased { get; set; }
    public int MSRP { get; set; }
    public double ScreenSize { get; set; }
}
public class PhonesController : Controller
{
    private List<PhoneBase> Phones;
    public PhonesController()
    {
        Phones = new List<PhoneBase>();
        var priv = new PhoneBase();
        priv.Id = 1;
        priv.PhoneName = "Priv";
        priv.Manufacturer = "BlackBerry";
        priv.DateReleased = new DateTime(2015, 11, 6);
        priv.MSRP = 799;
        priv.ScreenSize = 5.43;
        Phones.Add(priv);
    }
public ActionResult Index()
    {
        return View(Phones);
    }
    // GET: Phones/Details/5
    public ActionResult Details(int id)
    {
        return View(Phones[id - 1]);
    }

在这里，我通过使用表单集合创建视图插入新列表项

public ActionResult Create()
    {
        return View(new PhoneBase());
    }
    // POST: Phones/Create
    [HttpPost]
public ActionResult Create(FormCollection collection)
    {
        try
        {
            // TODO: Add insert logic here
            // configure the numbers; they come into the method as strings
            int msrp;
            double ss;
            bool isNumber;
            // MSRP first...
            isNumber = Int32.TryParse(collection["MSRP"], out msrp);
            // next, the screensize...
            isNumber = double.TryParse(collection["ScreenSize"], out ss);
            // var newItem = new PhoneBase();
            Phones.Add(new PhoneBase
            {
                // configure the unique identifier
                Id = Phones.Count + 1,
                // configure the string properties
                PhoneName = collection["PhoneName"],
                Manufacturer = collection["manufacturer"],
                // configure the date; it comes into the method as a string
                DateReleased = Convert.ToDateTime(collection["DateReleased"]),
                MSRP = msrp,
                ScreenSize = ss
            });

            //show results. using the existing Details view
            return View("Details", Phones[Phones.Count - 1]);
        }
        catch
        {
            return View();
        }
    }

查看整个列表不会显示通过创建视图添加的任何项目。