MVC5 排序和过滤答案

【问题标题】：MVC5 sorting and filteringMVC5 排序和过滤
【发布时间】：2016-01-09 18:30:24
【问题描述】：

我一直在尝试对一个项目进行排序，但遇到了困难。我已经查看了有关如何完成此操作的各种参考资料，但它仍然无法在我的项目中使用。我看过了

http://www.asp.net/mvc/overview/getting-started/getting-started-with-ef-using-mvc/sorting-filtering-and-paging-with-the-entity-framework-in-an-asp-net-mvc-application

和

http://www.c-sharpcorner.com/UploadFile/4b0136/perform-paging-searching-sorting-in-Asp-Net-mvc-5/

我拥有的是我的控制器

  public ActionResult Index(string sortBy, string searchString)
    {
        ViewBag.NameSortParm = String.IsNullOrEmpty(sortBy) ? "Surname desc" : "";
        ViewBag.DateSort = sortBy == "StartDate" ? "date desc" : "StartDate";
        var students = from s in db.Students
                       select s;
        if (!String.IsNullOrEmpty(searchString))
        {
            students = students.Where(s => s.Surname.Contains(searchString));
        }

        switch (sortBy)
        {
            case "name_desc":
                students = students.OrderByDescending(s => s.Surname);
                break;
            case "Date":
                students = students.OrderBy(s => s.StartDate);
                break;
            case "date_desc":
                students = students.OrderByDescending(s => s.StartDate);
                break;
            default:
                students = students.OrderBy(s => s.Surname);
                break;
        }

        return View(db.Students.ToList());
    }

我的看法

    @using (Html.BeginForm())
{
    <p>
        Find by name: @Html.TextBox("SearchString")
        <input type="submit" value="Search" />
    </p>
}
<table class="table">
    <tr>

        <th>
            @Html.DisplayNameFor(model => model.Name)
        </th>
        <th>
            @Html.ActionLink("Surname", "Index", new { sortBy = ViewBag.NameSortParm})
        </th>
        <th>
            @Html.ActionLink("Enrollment Date", "Index", new { sortOrder = ViewBag.DateSort})
        </th>
    </tr>

@foreach (var item in Model) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.Name)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Surname)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.StartDate)
        </td>
        <td>
            @Html.ActionLink("Edit", "Edit", new { id=item.ID }) |
            @Html.ActionLink("Details", "Details", new { id=item.ID }) |
            @Html.ActionLink("Delete", "Delete", new { id=item.ID })
        </td>
    </tr>
}

 </table>

这为我提供了视图中的操作链接，以及单击 localhost:5841/students?sortBy=Surname%20desc 和 localhost:5841/students?sortOrder=StartDate 后似乎正确的内容。我的问题是它们没有按应有的方式进行更改和排序。我错过了什么吗？

谢谢

【问题讨论】：

标签： asp.net-mvc-4

【解决方案1】：

您在控制器方法中进行排序，但最后您只使用返回一个未排序的集合

return View(db.Students.ToList());

再次调用数据库。相反，将 return 语句更改为

return View(students); // or students.ToList() depending on the model in the view

返回排序后的集合。

【讨论】：