@ Html.Dropdownlist列表未保存到数据库

在下面的示例中，我尝试将Asp.Net标识的“ aspnetusers”表“ Id”列中的ID保存到我的“ Application”表中。当我提交申请时，“全名”的下拉列表会填充，但不会保存到我的“应用”表中。提交应用程序后，我需要将aspnetusers表中的“ Id”保存到我的“应用程序”表中。帮助将不胜感激！

控制器：

private ApplicationDbContext db = new ApplicationDbContext();

public ActionResult Index()
{
    ViewBag.FullNameList = new SelectList(db.Users,"Id","FullName");
    return View();
}

// POST: Applications/Create
[ValidateAntiForgeryToken]
public ActionResult Index([Bind(Include = "Id,FullName, FirstName,MiddleInitial,LastName,")]   Application application)
{
    if (ModelState.IsValid)
    {
        ViewBag.FullNameList = new SelectList(db.Users, "Id", "FullName", application.ApplicationUser);
        db.Applications.Add(application);

        db.SaveChanges();

        return RedirectToAction("Thanks");
    }
}

看法：

<p>
      @Html.DropDownListFor(m => m.FullName, (SelectList)ViewBag.FullNameList, "Select Loan Officer")
</p>

模型：

public class Application
{
    public int ApplicationId { get; set; }

    [Required]
    [DisplayName("First Name")]
    public string FirstName { get; set; }

    [DisplayName("Middle Initial")]
    public string MiddleInitial { get; set; }

    [Required]
    [DisplayName("Last Name")]
    public string LastName { get; set; }

    public virtual string FullName {get; set; }

    public virtual ApplicationUser ApplicationUser { get; set; }
}