单击时无 Url 参数

Question

我正在尝试按照本教程进行操作，但将其重新用于我自己的应用程序。

https://docs.microsoft.com/en-us/aspnet/mvc/overview/older-versions/getting-started-with-ef-5-using-mvc-4/sorting-filtering-and-paging-with-the-entity-framework-in-an-asp-net-mvc-application

但是，按照教程中的说明单击标题时我遇到了一些问题，我的 url 没有更改为..

localhost:8000/Application?sortOrder=Date_desc

相反，我只得到以下内容

localhost:8000/应用程序

因此 sortOrder 始终为 null，并且排序会转移到开关中的默认项。

为什么会这样？据我所知，我已经遵循了教程。谁能解释我可能哪里出错了？

控制器

public ActionResult Index(string sortOrder, string currentFilter, string searchString, int? page)
    {
        ViewBag.CurrentSort = sortOrder;
        ViewBag.NameSortParam = String.IsNullOrEmpty(sortOrder) ? "Name_desc" : "";
        ViewBag.AppSSortParm = sortOrder == "AppS" ? "AppS_desc" : "AppS";

        if (searchString != null)
        {
            page = 1;
        }
        else
        {
            searchString = currentFilter;
        }

        ViewBag.CurrentFilter = searchString;

        var applications = from a in db.applications select a;

        if (!String.IsNullOrEmpty(searchString))
            applications = applications.Where(s => s.applicationDescription.ToUpper().Contains(searchString.ToUpper()));

        switch (sortOrder)
        {
            case "Name_desc":
                applications = applications.OrderByDescending(s => s.applicationDescription);
                break;
            case "AppS_desc":
                applications = applications.OrderByDescending(s => s.applicationWindowSecurity);
                break;
            case "AppS":
                applications = applications.OrderBy(s => s.applicationWindowSecurity);
                break;
            default:
                applications = applications.OrderBy(s => s.applicationDescription);
                break;
        }

        int pageSize = 8;
        int pageNumber = (page ?? 1);
        return View(applications.ToPagedList(pageNumber, pageSize));
    }

查看

    <th>
        @Html.ActionLink("App Description", "Index", new { sortOrder = ViewBag.NameSortParm }, htmlAttributes: new { @class = "control-label" })
    </th>
    <th>
        @Html.ActionLink("App Sec Over", "Index")
    </th>
    <th>
        @Html.ActionLink("App Window Sec", "Index", new { sortOrder = ViewBag.AppSSortParm }, htmlAttributes: new { @class = "control-label" })
    </th>

Answer 1

您需要将 actionLink 中的参数与您在控制器 Action 方法中期望的参数相匹配。请注意，ViewBag 是一个动态对象，因此很容易犯这种错误（因为它在运行时而不是编译时检查成员）。

单击时无 Url 参数

No Url Parameter on click

c#

asp.net-mvc

entity-framework-6

url-parameters