具有使用viewModel读取相关数据的IPagedList分页功能不起作用

Question

我正在创建一个Web应用程序以显示一组报告，并且在单击特定报告时，它应该在下面显示该报告的属性。我正在使用两种模型，即Report和Report_Property。 我有这样一种viewModel：

using WebReporting.Models;
using PagedList;
using PagedList.Mvc;
namespace WebReporting.ViewModel
{
  public class ReportPropertyIndex
  {
    public IPagedList<Report> Reports { get; set; }
    public IPagedList<Report_Property> Report_Properties { get; set; }
    public IEnumerable<Property> Properties { get; set; }
    public virtual Flow Flow { get; set; }
    public int? RequiredRole { get; set; }
    public bool IsGlobal { get; set; }
    public int? ShowTreeLevel { get; set; }

   }
 }

我在Reports_Controller中的索引方法：

using WebReporting.Models;
using PagedList;
using WebReporting.ViewModel;

namespace WebReporting.Controllers
{
public class ReportsController : Controller
{
    private DEV_COMPACT db = new DEV_COMPACT();

    // GET: Reports
    public ActionResult Index(string sortorder,string search,string  currentfilter,int? RPPage,int? page,int? reportpage,int? id,int? reportpropertyid)
    {

        int ReportPageNumber = (reportpage ?? 1);
        int RPpageNumber = (RPPage ?? 1);
        var viewModel = new ReportPropertyIndex();
        viewModel.Reports = db.Reports
        .Include(i => i.Report_Property.Select(c => c.Property))
        .OrderBy(i => i.ReportName).ToPagedList(ReportPageNumber, 5);
        if (id != null)
        {
            ViewBag.ReportID = id.Value;
            viewModel.Report_Properties = viewModel.Reports.Where(
                i => i.ReportID == id.Value).Single().Report_Property.ToPagedList(RPpageNumber,10);

        }

        ViewBag.CurrentSort = sortorder;
        ViewBag.UserNameSortParam = String.IsNullOrEmpty(sortorder) ? "report_desc" : "";
        ViewBag.ReportNameSortParm = String.IsNullOrEmpty(sortorder) ? "user_desc" : "";
        //var reports = db.Reports.Include(r => r.Flow).Include(r => r.User);
        if (search != null)
        {
            page = 1;
        }
        else
        {
            search = currentfilter;
        }

        ViewBag.currentfilter = search;


        int pageSize = 5;
        int pageNumber = (page ?? 1);
        pageNumber = page.HasValue ? Convert.ToInt32(page) : 1;


        return View(viewModel);  
    }

我的索引视图：

@model WebReporting.ViewModel.ReportPropertyIndex
@using PagedList;
@using PagedList.Mvc;
<link href="~/Content/PagedList.css" rel="stylesheet" type="text/css" />
@{
   ViewBag.Title = "Reports";

 }
 <style>
 </style> 
 <h2>Report Editor and Viewer</h2>
 @using (Html.BeginForm("Index", "Report", FormMethod.Get))
 {
  <p>
    Find by name: @Html.TextBox("SearchString")
    <input type="submit" value="search" />
  </p>
 }

 <p>
 @Html.ActionLink("Create New", "Create")
 </p>
 <div class="container" style="font-size:0.9rem;line-height:1.2rem;">
  <div class="row">
    <div class="col-md-2">
        <div class="panel-body">
            <table class="table table-hover table-striped table-bordered table-responsive-sm">
                <thead>
                    <tr>
                        <th>
                            @Html.DisplayNameFor(model => model.Flow.FlowName)
                        </th>
                        <th>
                            @Html.ActionLink("User Name", "Index", new { sortorder = ViewBag.NameSortParm, currentfilter = ViewBag.currenfilter })
                        </th>
                        <th>
                            @Html.ActionLink("Report Name", "Index", new { sortorder = ViewBag.ReportNameSortParm, currentfilter = ViewBag.currentfilter })
                        </th>
                        <th>
                            @Html.DisplayNameFor(model => model.IsGlobal)
                        </th>
                        <th>
                            @Html.DisplayNameFor(model => model.ShowTreeLevel)
                        </th>
                        <th>
                            @Html.DisplayNameFor(model => model.RequiredRole)
                        </th>
                        <th style="padding-left:250px"></th>
                    </tr>
                </thead>
                <tbody>
                    @foreach (var item in Model.Reports)
                    {
                        string selectedRow = "";
                        if (item.ReportID == ViewBag.ReportID)
                        {
                            selectedRow = "success";
                        }
                        <tr class="@selectedRow">

                            <td>
                                @Html.DisplayFor(modelItem => item.Flow.FlowName)
                            </td>
                            <td>
                                @Html.DisplayFor(modelItem => item.User.UserName)
                            </td>
                            <td>
                                @Html.DisplayFor(modelItem => item.ReportName)
                            </td>
                            <td>
                                @Html.DisplayFor(modelItem => item.IsGlobal)
                            </td>
                            <td>
                                @Html.DisplayFor(modelItem => item.ShowTreeLevel)
                            </td>
                            <td>
                                @Html.DisplayFor(modelItem => item.RequiredRole)
                            </td>
                            <td>
                                @Html.ActionLink("Select", "Index", new { id = item.ReportID }) |
                                @Html.ActionLink("Edit", "Edit", new { id = item.ReportID }) |
                                @Html.ActionLink("Details", "Details", new { id = item.ReportID }) |
                                @Html.ActionLink("Delete", "Delete", new { id = item.ReportID })
                            </td>
                        </tr>
                    }
                </tbody>

            </table>

在第一页上一切正常，但是当我单击下一页并在该页上选择报告时，就会出现问题，即当我收到错误消息时：System.InvalidOperationException: 'Sequence contains no elements' 罪魁祸首似乎在这里：

if (id != null)
        {
            ViewBag.ReportID = id.Value;
            viewModel.Report_Properties = viewModel.Reports.Where(
                i => i.ReportID ==id.Value).Single().Report_Property.ToPagedList(RPpageNumber,10);

        }

我还不能弄清楚是什么问题，请帮助！！