不包含ToPagedList的定義

Question

嘗試在我的Controller中實現PagedList時，我不斷收到此錯誤。 確切的錯誤讀取

'DataIntelligence.Models.Execution'不包含'ToPagedList'的定義，並且沒有擴展方法'ToPagedList'可以找到接受類型'DataIntelligence.Models.Execution'的第一個參數（你是否缺少using指令或程序集引用？）`

而且我不知道為什么。 我看過類似的問題，但似乎找不到我要找的答案。 我想知道是否有人可以提供幫助。

調節器

using DataIntelligence.Models;
using PagedList;
using PagedList.Mvc;
using System;
using System.Linq;
using System.Web.Mvc;

public ActionResult Execution(int? page, int id = 0)
{
    var execution = db.Executions.Find(id);

    if (execution == null)
    {
        return HttpNotFound();
    }

    ViewBag.ExecutionSeconds = (execution.End - execution.Start).ToString(@"dd\.hh\:mm\:ss\.fff");

    int pageSize = Int32.Parse(System.Configuration.ConfigurationManager.AppSettings["DefaultPageSize"]);
                int pageNumber = (page ?? 1);
    return View(execution.ToPagedList(pageNumber, pageSize));
}

執行模型

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Web;


namespace DataIntelligence.Models
{
    [Table("Execution")]
    public class Execution
    {
        public int Id { get; set; }
        public Int16 PackageId { get; set; }
        public DateTime Start { get; set; }
        public DateTime End { get; set; }
        public Boolean Successful { get; set; }

        public virtual ICollection<Step> Steps { get; set; }
    }
}

視圖

@model PagedList.IPagedList<DataIntelligence.Models.Execution>
@using PagedList.Mvc;

<link href="Content/PagedList.css" rel="stylesheet" type="text/css" />

@{
    ViewBag.Title = "Execution Details";
}
<script language="javascript" type="text/javascript" src="jquery-1.8.3.js">    </script>
<script>
    function goBack() {
        window.history.back();
    }
</script>
<div class="jumbotron">
    <h2>Execution Details</h2>
</div>

<fieldset>
    <legend>Execution Id - @Html.DisplayFor(model => model.Id)</legend>

    <div class="row">
        <div class="col-sm-3">
            <div class="display-label">
                @Html.DisplayNameFor(model => model.PackageId)
            </div>
            <div class="display-field">
                <a href="@Url.Action("Package", new { id=Model.PackageId})"> @Html.DisplayFor(model => model.PackageId) </a>
            </div>
        </div>

        <div class="col-sm-3">
            <div class="display-label">
                @Html.DisplayNameFor(model => model.Start)
            </div>
            <div class="display-field">
                @Html.DisplayFor(model => model.Start)
            </div>
        </div>
        <div class="col-sm-3">
            <div class="display-label">
                @Html.DisplayNameFor(model => model.End)
            </div>
            <div class="display-field">
                @Html.DisplayFor(model => model.End)
            </div>
        </div>
        <div class="col-sm-3">
            <div class="display-label">
                Execution Time
            </div>
            <div class="display-field">
                @ViewBag.ExecutionSeconds
            </div>
        </div>
    </div>
    <div class="row">
        <div class="col-sm-3">
            <div class="display-label">
                @Html.DisplayNameFor(model => model.Successful)
            </div>
            <div class="display-field">
                @Html.DisplayFor(model => model.Successful)
            </div>
        </div>
    </div>
    <br />
</fieldset>

<table>
    <tr>
        <th>
            Step ID
        </th>
        <th id="stepname">
            Name
        </th>
        <th id="stepdate">
            Date
        </th>
    </tr>

    @foreach (var step in Model.Steps) {
       <tr>
            <td>
               @Html.DisplayFor(modelItem => step.Id)
            </td>
            <td id="steps">
                @Html.DisplayFor(modelItem => step.Name)
            </td>
            <td id="date">
                @Html.DisplayFor(modelItem => step.Date)
            </td>
        </tr>
    }
</table>
<button class="btn btn-link" onclick="goBack()" style="padding-right: 0px; padding-top: 0px; padding-bottom: 0px; padding-left: 0px;">Back</button>

Page @(Model.Steps.PageCount < Model.Steps.PageNumber ? 0 :  Model.Steps.PageNumber) of @Model.Steps.PageCount
@Html.PagedListPager(Model.Steps, page => Url.Action("Execution", new { page, sortOrder = ViewBag.CurrentSort}))

Answer 1

DbSet.Find方法返回實體的單個實例，而不是枚舉。 因此將ToPagedList應用於此是沒有意義的。 如果您確實希望將其包裝在分頁列表中，則可以將查詢更改為：

var executions = db.Executions.Where(e => e.Id == id);

這將為您提供僅具有單個值的IEnumerable結果。

編輯

閱讀完您的評論后，您似乎確實只想對Steps屬性進行分頁。 要做到這一點，最好創建視圖模型而不是將數據庫實體直接傳遞給視圖，請注意我如何將Steps屬性的類型更改為分頁列表：

public class ExecutionViewModel
{
    public int Id { get; set; }
    public Int16 PackageId { get; set; }
    public DateTime Start { get; set; }
    public DateTime End { get; set; }
    public Boolean Successful { get; set; }

    public virtual PagedList.IPagedList<Step> Steps { get; set; }
}

沒有你的控制器變成這樣：

public ActionResult Execution(int? page, int id = 0)
{
    var execution = db.Executions.Find(id);

    if (execution == null)
    {
        return HttpNotFound();
    }

    ViewBag.ExecutionSeconds = (execution.End - execution.Start).ToString(@"dd\.hh\:mm\:ss\.fff");

    int pageSize = Int32.Parse(System.Configuration.ConfigurationManager.AppSettings["DefaultPageSize"]);
    int pageNumber = (page ?? 1);

    var executionModel = new ExecutionViewModel
    {
        Id = execution.Id,
        PackageId = execution.PackageId,
        Start = execution.Start,
        End = execution.End,
        Successful = execution.Successful,
        Steps = execution.Steps.ToPagedList(pageNumber, pageSize)
    };
    return View(executionModel);
}

並且不要忘記更改視圖以獲取新對象：

@model DataIntelligence.ViewModels.ExecutionViewModel

Answer 2

通過NuGet添加以下內容：

PM> Install-Package PagedList.MVC 

在控制器中，添加以下內容：

using PagedList;

在您的視圖中，添加以下內容：

@using PagedList.Mvc;