Question

我正在学习asp.net mvc 4并按照Contoso大学的教程进行操作，我是第10部分的第3部分。http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/sorting-filtering-and-paging-with-the-entity-framework-in-an-asp-net-mvc-application

问题我特别关注过滤部分。我注意到，当我有一个搜索字符串并点击搜索时，它会给我我想要的结果。但是，当我单击姓氏或注册以对结果进行排序时，它将为我提供包括所有学生的排序列表。以下是Controller代码：

public ViewResult Index(string sortOrder, string searchString)
{
ViewBag.NameSortParm = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "";
ViewBag.DateSortParm = sortOrder == "Date" ? "date_desc" : "Date";
var students = from s in db.Students
               select s;
if (!String.IsNullOrEmpty(searchString))
{
    students = students.Where(s =>s.LastName.ToUpper().Contains(searchString.ToUpper())
                           || s.FirstMidName.ToUpper().Contains(searchString.ToUpper()));
}
switch (sortOrder)
{
    case "name_desc":
        students = students.OrderByDescending(s => s.LastName);
        break;
    case "Date":
        students = students.OrderBy(s => s.EnrollmentDate);
        break;
    case "date_desc":
        students = students.OrderByDescending(s => s.EnrollmentDate);
        break;
    default:
        students = students.OrderBy(s => s.LastName);
        break;
}

return View(students.ToList());

}

当我处于调试模式时，我注意到即使搜索框中仍然包含原始搜索字符串，传入控制器的Index（）d的searchString也为null。如何更改代码以便我可以对筛选结果进行排序？谢谢！

Answer 1

将过滤器保存到ViewBag并更新排序链接以包含过滤器

ViewBag.CurrentFilter = searchString;

@Html.ActionLink("Last Name", "Index", new { sortOrder=ViewBag.NameSortParm, searchString=ViewBag.CurrentFilter })

ASP.NET MVC 4，contoso大学示例，如何对筛选结果进行排序并正确显示

1 个答案: