Question

我在表格中显示了大量数据，让我们说一长串用户（名字和姓氏），所以我设置了一个分页功能，通过PagedList NuGet包按页显示元素。我受到本教程的启发：https://docs.microsoft.com/en-us/aspnet/mvc/overview/getting-started/getting-started-with-ef-using-mvc/sorting-filtering-and-paging-with-the-entity-framework-in-an-asp-net-mvc-application

我在视图中实现了一个下拉列表，这样我就可以直接选择每页显示的元素数量。我设法包含一个jQuery脚本，只要下拉列表中有一个新的选定值，就会更新页面大小。

使用上述教程，我还添加了搜索功能：以搜索表单提交字符串可以过滤数据。

我的问题是：通过在下拉列表中选择新值来更改页面大小完成搜索后不起作用：重置搜索结果，所有条目正在显示。我想我忘了在某个地方传递一些参数，但我无法弄清楚在哪里......

这是我的控制器：

public ActionResult Index(string sortOrder, string currentFilter, string searchString, int? page, int? PageSize) // Sort order is passed to view in order to keep it intact while clicking in another page link ViewBag.CurrentSort = sortOrder; // Ascending or descending sorting by first or last name according to sortOrder value ViewBag.LastNameSortParm = String.IsNullOrEmpty(sortOrder) ? "lastname_desc" : ""; ViewBag.FirstNameSortParm = sortOrder == "firstname" ? "firstname_desc" : "firstname"; // Not sure here if (searchString == null) { searchString = currentFilter; } // Pass filtering string to view in order to maintain filtering when paging ViewBag.CurrentFilter = searchString; var users = from u in _db.USER select u; // FILTERING if (!String.IsNullOrEmpty(searchString)) { users = users.Where(u => u.lastname.Contains(searchString) || u.firstname.Contains(searchString) } // Ascending or descending filtering by first/last name switch (sortOrder) { case "lastname": // Ascending last name users = users.OrderBy(u => u.lastname); break; case "lastname_desc": // Descending last name users = users.OrderByDescending(u => u.lastname); break; case "firstname": // Ascending first name users = users.OrderBy(u => u.firstname); break; case "firstname_desc": // Descending first name users = users.OrderByDescending(u => u.firstname); break; default: users = users.OrderBy(u => u.lastname); break; } // DROPDOWNLIST FOR UPDATING PAGE SIZE int count = _db.USER.OrderBy(e => e.Id).Count(); // Total number of elements // Populate DropDownList ViewBag.PageSize = new List<SelectListItem>() { new SelectListItem { Text = "10", Value = "10", Selected = true }, new SelectListItem { Text = "25", Value = "25" }, new SelectListItem { Text = "50", Value = "50" }, new SelectListItem { Text = "100", Value = "100" }, new SelectListItem { Text = "All", Value = count.ToString() } }; int pageNumber = (page ?? 1); int pageSize = (PageSize ?? 10); ViewBag.psize = pageSize; return View(users.ToPagedList(pageNumber, pageSize)); }

我的Index.cshtml视图：

<script src="~/Scripts/jquery-3.2.1.js" type="text/javascript"></script> <script type="text/javascript"> $(function () { // Submit pageSizeForm when another pageSize value is selected $("#pageSize").change(function () { $("#pageSizeForm").submit(); }); }); </script> @model PagedList.IPagedList<AfpaSIPAdmin.Models.USER> @using PagedList.Mvc; <link href="~/Content/PagedList.css" rel="stylesheet" type="text/css" /> @{ ViewBag.Title = "Users management"; } <h1>Users management</h1>  <p> @Html.ActionLink("Create new user", "Create") </p>  @using (Html.BeginForm("Index", "Users", FormMethod.Get, new { id = "filterForm" })) { <p> Filter: @Html.TextBox("SearchString", ViewBag.CurrentFilter as string, new { @placeholder = "First or last name..." }) <input type="submit" value="Apply"/> </p> }  <table class="table"> <tr> <th> @Html.ActionLink("Last name", "Index", new { sortOrder = ViewBag.LastNameSortParm, currentFilter = ViewBag.CurrentFilter }) </th> <th> @Html.ActionLink("First name", "Index", new { sortOrder = ViewBag.FirstNameSortParm, currentFilter = ViewBag.CurrentFilter }) </th> <th style="min-width: 170px"></th> </tr> @foreach (var item in Model) { <tr> <td style = "min-width: 150px"> @Html.DisplayFor(modelItem => item.lastname) </td> <td style = "min-width: 150px"> @Html.DisplayFor(modelItem => item.firstname) </td> <td>  <a href="@Url.Action("Edit", "Users", new { id = item.Id })" title="Edit"> <img src="~/Content/images/edit.gif" /> </a> <a href="@Url.Action("Details", "Users", new { id = item.Id })" title="Details"> <img src="~/Content/images/info.gif" /> </a> <a href="@Url.Action("Delete", "Users", new { id = item.Id })" title="Delete"> <img src="~/Content/images/delete.gif" /> </a> </td> </tr> } </table> <br/>  @using (Html.BeginForm("Index", "Users", FormMethod.Get, new { id = "pageSizeForm" })) { <div class="pager"> Page @(Model.PageCount < Model.PageNumber ? 0 : Model.PageNumber) sur @Model.PageCount<br/> @Model.Count of @Model.TotalItemCount elements @Html.PagedListPager(Model, page => Url.Action("Index", new { page, sortOrder = ViewBag.CurrentSort, currentFilter = ViewBag.CurrentFilter, searchString = ViewBag.CurrentFilter, pageSize = ViewBag.psize }))  Elements per page : @Html.DropDownList("pageSize") </div> }

Answer 1

原因是因为你有2个表格。当您提交包含文本框的第一个表单时，您发送回控制器的唯一值是SearchString，并且您方法中的所有其他参数将是它们的默认值（例如，当您返回视图时，{{1}默认为PageSize，因此即使之前选择的用户说50，也只返回10条记录。

同样，当您提交包含页面大小下拉列表的第二个表单时，null的值将为SearchString，因为它未在请求中发送。

您需要只有一个包含两个表单控件的表单。如果要发送其他属性（例如当前排序顺序），则可以将其作为查询字符串值添加到表单元素中（例如，null

我还强烈建议您使用包含视图中所需属性的视图模型，并强烈绑定它们而不是使用@using(Html.BeginForm("Index", "Users", new { sortOrder = .... }, FormMethod.Get))

ViewBag

查看

public class UsersVM
{
    public string SearchString { get; set; }
    public int PageSize { get; set; }
    public IEnumerable<SelectListItem> PageSizeOptions { get; set; }
    .....
    public IPagedList<USER> Users { get; set; }
}

并在控制器方法中，初始化@model UsersVM ... @using(Html.BeginForm("Index", "Users", FormMethod.Get)) { @Html.LabelFor(m => m.SearchString) @Html.TextBoxFor(m => m.SearchString) @Html.LabelFor(m => m.PageSize) @Html.DropDownListFor(m => m.PageSize, Model.PageSizeOptions) <input type="submit" value="Filter" /> } .... <div class="pager"> Page @(Model.Users.PageCount < Model.Users.PageNumber ? 0 : Model.Users.PageNumber) .... @Html.PagedListPager(Model.Users, page => Url.Action("Index", new { page, sortOrder = Model.CurrentSort, currentFilter = Model.CurrentFilter, searchString = Model.CurrentFilter, pageSize = Model.PageSize })) </div>的新实例并分配其属性

UsersVM

更改页面上显示的表格元素数量会重置我的搜索结果

1 个答案: