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我正在学习 MVC，我正在存储用户的出生日期以显示他的年龄。数据已正确保存。然后按照本教程对数据进行排序。它适用于名字和姓氏，但在按年龄排序时会抛出异常 LINQ to Entities 仅支持无参数构造函数和初始化程序。
我的行动准则是

        public ActionResult Index(string sortOrder, int? page, string currentFilter, string q)
    {
        ViewBag.CurrentSort = sortOrder;
        ViewBag.FNSortParam = string.IsNullOrWhiteSpace(sortOrder) ? "FName_Desc" : "";
        ViewBag.LNSortParam = sortOrder == "LName" ? "LN_Desc" : "LName";
        ViewBag.AgeSortParam = sortOrder == "Age" ? "Age_Desc" : "Age";
        var query = q;
        if (query != null)
            page = 1;
        else
            query = currentFilter;

        var users = db.MyAppUsers.Select(a => a);

        if (!string.IsNullOrWhiteSpace(query))
        {
            var nQuery = query.ToUpper();
            users = users.Where(a => a.FName.ToUpper().Contains(nQuery) ||
              a.LName.ToUpper().Contains(nQuery) || a.Email.Contains(nQuery));
        }
        switch (sortOrder)
        {
            case "FName_Desc":
                users = users.OrderByDescending(a => a.FName);
                break;
            case "LName":
                users = users.OrderBy(a => a.LName);
                break;
            case "LN_Desc":
                users = users.OrderByDescending(a => a.LName);
                break;
            case "Age":
                users = users.OrderBy(a => new DateTime(DateTime.Now.Subtract(a.DOB).Ticks));
                break;
            case "Age_Desc":
                users = users.OrderByDescending(a => new DateTime(DateTime.Now.Subtract(a.DOB).Ticks));
                break;
            default:
                users = users.OrderBy(a => a.FName);
                break;
        }
    //            public DateTime Age
    //{
    //    get { return new DateTime(DateTime.UtcNow.Subtract(DOB).Ticks); }
    //}

    int pageSize = 3;
        int pageNumber = (page ?? 1);
        return View(users.ToPagedList(pageNumber, pageSize));
    }

而对于视图是

    @foreach (var item in Model)
{
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.FName)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.LName)
        </td>
        <td>
            @{
                var age = new DateTime(DateTime.UtcNow.Subtract(item.DOB).Ticks);
                @Html.DisplayTextFor(modelItem => age.Year)
            }
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Email)
        </td>
    </tr>
                }

我想不通。有人可以帮忙吗？

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