Swift：gettimeofday和Unsafe Pointers(Swift: gettimeofday and Unsafe Pointers)

 我解决了这个问题（感谢大家的提示）。 这适用于任何可能遇到类似问题的人。 
 
 我改变了我的Create方法，如下所示： 
 
// GET: /Products/Create
public ActionResult Create()
{
    var p = new AddNewProductViewModel();
    p.Categories = entities.ProductCategories.ToList();
    return View(p);
}
 
 我的AddNewProductViewModel看起来像这样： 
 
using AccessorizeForLess.Data;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Web;

namespace AccessorizeForLess.ViewModels
{
    public class AddNewProductViewModel
    {
        public string Name { get; set; }

        [DataType(DataType.MultilineText)]
        public string Description { get; set; }

        public decimal Price { get; set; }

        public string AltText { get; set; }

        public int Quantity { get; set; }

        public HttpPostedFileBase Image { get; set; }

        public int SelectedCategoryId {get;set;}
        public List<ProductCategory> Categories { get; set; }
        public ProductCategory Category { get; set; }
    }
}
 
 在我看来： 
 
<div class="form-group">
    @Html.LabelFor(model => model.SelectedCategoryId, "Category",new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.DropDownListFor(model => model.SelectedCategoryId, new SelectList(Model.Categories, "CategoryId", "CategoryName"), "- Please Select -")
        @Html.ValidationMessageFor(model => model.SelectedCategoryId)
    </div>
</div>
 
 感谢大家的帮助:) 

I solved the issue (thanks to everyone for the tips). This is for anyone who may be having issues like I was.
 
I changed my Create method to look like so:
 
// GET: /Products/Create
public ActionResult Create()
{
    var p = new AddNewProductViewModel();
    p.Categories = entities.ProductCategories.ToList();
    return View(p);
}
 
My AddNewProductViewModel looks like so:
 
using AccessorizeForLess.Data;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Web;

namespace AccessorizeForLess.ViewModels
{
    public class AddNewProductViewModel
    {
        public string Name { get; set; }

        [DataType(DataType.MultilineText)]
        public string Description { get; set; }

        public decimal Price { get; set; }

        public string AltText { get; set; }

        public int Quantity { get; set; }

        public HttpPostedFileBase Image { get; set; }

        public int SelectedCategoryId {get;set;}
        public List<ProductCategory> Categories { get; set; }
        public ProductCategory Category { get; set; }
    }
}
 
The in my view:
 
<div class="form-group">
    @Html.LabelFor(model => model.SelectedCategoryId, "Category",new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.DropDownListFor(model => model.SelectedCategoryId, new SelectList(Model.Categories, "CategoryId", "CategoryName"), "- Please Select -")
        @Html.ValidationMessageFor(model => model.SelectedCategoryId)
    </div>
</div>
 
Thanks for the help everyone :)