您如何通过 ASP.net 内核中的 IEnumerable ViewModel 进行分页？

Question

我正在尝试向 asp.net 中的视图添加分页。 这是我尝试将分页添加到我创建的视图的地方。 当页面仅包含 @Model ViewModel 行时，我的动态分页有效。 我还没有看到任何关于如何对这个特定的东西进行分页的信息，我也没有找到太多关于它的信息。 是否有明显的遗漏或者我需要重写我的代码来添加分页。

这是问题发生位置的链接。 我得到的错误是 CS1061“IEnumerable 不包含 PageNUMeringInfo 的定义。

@model IEnumerable<byudigs.Models.ViewModels.ViewModel>


<link href="~/css/Table.css" rel="stylesheet" />

<br />
<br />
<br />
<br />
<section class="get-in-touch">
    <h1 class="title">Mummy Finder</h1>
    <div class="container py-5">
        @*<header class="text-center text-white">
                <h1 class="display-4">Bootstrap Datatables</h1>
                <p class="lead mb-0">
                    Using Bootstrap 4 and <a href="https://datatables.net/examples/styling/bootstrap4.html" class="text-white font-italic">
                        <u>Datatables</u>
                    </a>, add interaction controlsto your HTML tables.
                </p>
                <p class="font-italic">
                    Snippet By
                    <a href="https://bootstrapious.com" class="text-white">
                        <u>Bootstrapious</u>
                    </a>
                </p>
            </header>*@
        @*<input name="searchString" />*@
        <div class="row py-5">
            <div class="col-lg-10 mx-auto">
                <div class="card rounded shadow border-0">
                    <div class="card-body p-5 bg-white rounded">
                        <div class="table-responsive">
                            <table class="table table-striped table-bordered">
                                <thead>
                                    <tr>
                                        <!--This is creating the headers of the table-->
                                        <th style="padding-left:8px; padding-right:8px;">Location:</th>
                                        <th style="padding-left:8px; padding-right:8px;">South to Head:</th>
                                        <th style="padding-left:8px; padding-right:8px;">South to Feet:</th>
                                        <th style="padding-left:8px; padding-right:8px;">West to Head:</th>
                                        <th style="padding-left:8px; padding-right:8px;">West to Feet:</th>
                                        <th style="padding-left:8px; padding-right:8px;">Length:</th>
                                        <th style="padding-left:8px; padding-right:8px;">Burial Depth:</th>
                                        <th style="padding-left:8px; padding-right:8px;">Hair:</th>
                                        <th style="padding-left:8px; padding-right:8px;">Gender:</th>
                                        <th style="padding-left:8px; padding-right:8px;">Head Direction:</th>
                                        <th style="padding-left:8px; padding-right:8px;">Artifact Found?</th>
                                        <th style="padding-left:8px; padding-right:8px;">Date Discovered</th>
                                    </tr>
                                </thead>
                                <tbody>
                                    @foreach (var x in Model)
                                    {
                                        <tr>
                                            <!--This is assigning the model variables to the list so that it can be seen in this view-->
                                            <td style="padding-left:8px; padding-right:8px;"> @x.burialadvanced.HairColor @x.burial.BurialNum @x.plot.BurialLocationNs @x.plot.LowPairNs/@x.plot.HighPairNs @x.plot.BurialLocationEw @x.plot.LowPairEw/@x.plot.HighPairEw @x.sublocation.Direction #@x.burial.BurialNum @x.burial.BurialSubnum</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.SouthToHead</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.SouthToFeet</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.EastToHead</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.EastToFeet</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.LengthOfRemains</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.BurialDepth</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.HairColor</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.GenderBodyCol</td>
                                            <td style="padding-left:8px; padding-right:8px;">@x.burialadvanced.HeadDirection</td>
                                            <th style="padding-left:8px; padding-right:8px;">@x.burialadvanced.ArtifactFound</th>
                                            <th style="padding-left:8px; padding-right:8px;">@x.burialadvanced.MonthFound/@x.burialadvanced.DayFound/@x.burialadvanced.YearFound</th>
                                        </tr>

                                    }
                                </tbody>
                            </table>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>
</section>
<!--paginated links-->
<div page-info="@Model.PageNumberingInfo"
     page-action="BurialList"
     page-classes-enabled="true"
     page-class="btn"
     page-class-normal="btn-outline-secondary"
     page-class-selected="btn-primary">
</div>
}

这是我的 controller 的 BurialList 部分。

        [AllowAnonymous]
        public IActionResult BurialList(string searchString, int pageNum=1)
        {
            ViewBag.Burial = _context.Burial;
            ViewBag.BurialAdvanced = _context.BurialAdvanced;
            ViewBag.Sublocation = _context.Sublocation;
            ViewBag.Date = _context.Date;
            //var burials = _context.BurialAdvanced.FromSqlRaw("SELECT * from burial_advanced ba join burial b on ba.burial_id = b.burial_id join plot p on b.plot_id = p.plot_id join sublocation s on b.sublocation_id = s.sublocation_id");
           
            //Filter by hair color
            if (!String.IsNullOrEmpty(searchString))
            {
                List<Burial> burial = _context.Burial.ToList();
                List<Plot> plot = _context.Plot.ToList();
                List<Sublocation> sublocation = _context.Sublocation.ToList();
                List<BurialAdvanced> burialadvanced = _context.BurialAdvanced.Where(x => x.HairColor.Contains(searchString)).ToList();
               var burialRecord = from ba in burialadvanced
                               join b in burial on ba.BurialId equals b.BurialId into table1
                               from b in table1.ToList()
                               join p in plot on b.PlotId equals p.PlotId into table2
                               from p in table2.ToList()
                               join s in sublocation on b.SublocationId equals s.SublocationId into table3
                               from s in table3.ToList()
                               select new ViewModel
                               {
                                   burial = b,
                                   burialadvanced = ba,
                                   plot = p,
                                   sublocation = s,
                                   PageNumberingInfo = new PageNumberingInfo
                                   {
                                       CurrentPage = pageNum,
                                       NumItemsPerPage = PageSize,
                                       TotalNumItems = 500
                                       //TotalNumItems = (burialId == null ? _repository.Burials.Count() :
                                       //    _repository.Burials.Where(b => b.BurialId == burialId).Count())
                                   },
            };
                return View(burialRecord);



            }
            else
            {
                List<Burial> burial = _context.Burial.ToList();
                List<Plot> plot = _context.Plot.ToList();
                List<Sublocation> sublocation = _context.Sublocation.ToList();
                List<BurialAdvanced> burialadvanced = _context.BurialAdvanced.ToList();

                var burialRecord = from ba in burialadvanced
                                   join b in burial on ba.BurialId equals b.BurialId into table1
                                   from b in table1.ToList()
                                   join p in plot on b.PlotId equals p.PlotId into table2
                                   from p in table2.ToList()
                                   join s in sublocation on b.SublocationId equals s.SublocationId into table3
                                   from s in table3.ToList()
                                   select new ViewModel
                                   {
                                       burial = b,
                                       burialadvanced = ba,
                                       plot = p,
                                       sublocation = s
                                   };
                return View(burialRecord);
            }



            //return View(burialRecord.ToList());
        }

这是我的 PaginationTagHelper class 位于我的基础设施文件夹中

namespace byudigs.Infrastructure
{
    [HtmlTargetElement("div", Attributes = "page-info")]
    public class PaginationTagHelper : TagHelper
    {
        private IUrlHelperFactory urlHelperFactory;
        public PaginationTagHelper(IUrlHelperFactory uhf)
        {
            urlHelperFactory = uhf;
        }


        //public string TeamName { get; set; }

        //our own key value dictionary for team name and paging info
        [HtmlAttributeName(DictionaryAttributePrefix = "page-url-")]
        public Dictionary<string, object> KeyValuePairs { get; set; } = new Dictionary<string, object>();

        [HtmlAttributeNotBound]
        [ViewContext]
        public ViewContext ViewContext { get; set; }
        public PageNumberingInfo PageInfo { get; set; }
        public string PageAction { get; set; }


        public bool PageClassesEnabled { get; set; } = false;
        public string PageClass { get; set; }
        public string PageClassNormal { get; set; }
        public string PageClassSelected { get; set; }


        public override void Process(TagHelperContext context, TagHelperOutput output)
        {
            IUrlHelper urlHelper = urlHelperFactory.GetUrlHelper(ViewContext);

            TagBuilder finishedTag = new TagBuilder("div");

            //loop that will append a link for every page
            for (int i = 1; i <= PageInfo.NumPages; i++)
            {
                TagBuilder individualTag = new TagBuilder("a");

                if (PageClassesEnabled)
                {
                    //add Css capabilities if the page exists
                    individualTag.AddCssClass(PageClass);
                    individualTag.AddCssClass(i == PageInfo.CurrentPage ? PageClassSelected : PageClassNormal);
                }

                KeyValuePairs["pageNum"] = i;
                individualTag.Attributes["href"] = urlHelper.Action("BurialList", KeyValuePairs);
                individualTag.InnerHtml.Append(i.ToString());

                finishedTag.InnerHtml.AppendHtml(individualTag);
            }

            output.PostContent.AppendHtml(finishedTag.InnerHtml);
        }
    }
}

这是我的 PageNumberingInfo 视图 model

namespace byudigs.Models.ViewModels
{
    public class PageNumberingInfo
    {
        //info to get from controller, pass to view as defaults for the structure of the page
        public int NumItemsPerPage { get; set; }
        public int CurrentPage { get; set; }
        public int TotalNumItems { get; set; }

        //calculate pages
        //cast one of the properties as a decimal to force decimal division
        public int NumPages => (int)Math.Ceiling((decimal)TotalNumItems / NumItemsPerPage);
    }
}

这是我的视图模型

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace byudigs.Models.ViewModels
{
    public class ViewModel
    {
        public Burial burial { get; set; }
        public BurialAdvanced burialadvanced { get; set; }
        public Plot plot { get; set; }
        public Sublocation sublocation { get; set; }

        public PageNumberingInfo PageNumberingInfo { get; set; }
    }
}

Answer 1

在 select new ViewModel {... } 之前执行此操作：

skip (pageNum - 1) * pageSize
take pageSize

编辑

因此，您将要编辑您的 ViewModel class 并为个人埋葬记录创建一个新的 class。

public class ViewModel {
    PageNumberingInfo PageNumberingInfo { get; set; },
    BurialRecord BurialRecord { get; set; }
}

public class BurialRecord {
    Burial Burial { get; set; }
    BurialAdvanced BurialAdvanced { get; set; }
    Plot Plot { get; set; }
    Sublocation Sublocation {get;set;
}

现在在您的 controller 中：

var burialRecords = from ba in burialadvanced
                           join b in burial on ba.BurialId equals b.BurialId into table1
                           from b in table1.ToList()
                           join p in plot on b.PlotId equals p.PlotId into table2
                           from p in table2.ToList()
                           join s in sublocation on b.SublocationId equals s.SublocationId into table3
                           from s in table3.ToList()
                           select new BurialRecord
                           {
                               burial = b,
                               burialadvanced = ba,
                               plot = p,
                               sublocation = s,
        };

var model = new ViewModel 
{
    PageNumberingInfo = new PageNumberingInfo
        {
            CurrentPage = pageNum,
            NumItemsPerPage = PageSize,
            TotalNumItems = 500
        },
    BurialRecords = burialRecords
};