asp.net mvc 简易通用自定义Pager实现分页

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Intro

一个WEB应用程序中经常会用到数据分页，本文将实现一个简单通用的分页组件，包含一个 PagerModel (用来保存页码信息)，一个 HtmlHelper 的 Pager 扩展方法和一个 PagedListModel<T> 分页数据模型。

pager效果图如下：

PagerModel 分页模型

PagerModel 用来保存分页信息，代码实现如下：

 1     /// <summary>
 2     /// PagerModel 分页模型
 3     /// </summary>
 4     public class PagerModel
 5     {
 6         public int PageIndex { get; set; }
 7 
 8         public int PageSize { get; set; }
 9 
10         public int PageCount { get; private set; }
11 
12         public int TotalCount { get; set; }
13 
14         public PagerModel(int totalCount)
15         {
16             PageIndex = 1;
17             PageSize = 10;
18             TotalCount = totalCount;
19             PageCount = Convert.ToInt32(Math.Ceiling(TotalCount * 1.0 / PageSize));
20         }
21 
22         public PagerModel(int pageSize, int totalCount)
23         {
24             PageIndex = 1;
25             PageSize = pageSize;
26             TotalCount = totalCount;
27             PageCount = Convert.ToInt32(Math.Ceiling(TotalCount * 1.0 / PageSize));
28         }
29 
30         public PagerModel(int pageIndex, int pageSize, int totalCount)
31         {
32             PageIndex = pageIndex;
33             PageSize = pageSize;
34             TotalCount = totalCount;
35             PageCount = Convert.ToInt32(Math.Ceiling(TotalCount * 1.0 / PageSize));
36         }
37     }

PagerModel

  /// <summary>
  /// PagerModel 分页模型
  /// </summary>
  public class PagerModel
  {
      public int PageIndex { get; set; }

      public int PageSize { get; set; }

      public int PageCount { get; private set; }

      public int TotalCount { get; set; }

      public PagerModel(int totalCount)
      {
          PageIndex = 1;
          PageSize = 10;
          TotalCount = totalCount;
          PageCount = Convert.ToInt32(Math.Ceiling(TotalCount * 1.0 / PageSize));
      }

      public PagerModel(int pageSize, int totalCount)
      {
          PageIndex = 1;
          PageSize = pageSize;
          TotalCount = totalCount;
          PageCount = Convert.ToInt32(Math.Ceiling(TotalCount * 1.0 / PageSize));
      }

      public PagerModel(int pageIndex, int pageSize, int totalCount)
      {
          PageIndex = pageIndex;
          PageSize = pageSize;
          TotalCount = totalCount;
          PageCount = Convert.ToInt32(Math.Ceiling(TotalCount * 1.0 / PageSize));
      }
  }

Pager扩展方法

Pager扩展方法可根据自己的需求进行定制话实现，Pager扩展方法需要一个PagerModel类型的参数来生成页码，我这里是用的bootstrap的样式来做的分页，整个系统用的是同一个样式的分页所以把样式直接写死在代码里了。
Pager这里的代码重构做的不是太好：

样式直接写死，前端不好维护

 1     /// <summary>
 2     /// PagerHelper 分页帮助类
 3     /// </summary>
 4     public static class PagerHelper
 5     {
 6         public static MvcHtmlString Pager(this HtmlHelper helper, PagerModel pager)
 7         {
 8             StringBuilder sbHtmlText = new StringBuilder();
 9             sbHtmlText.Append("<div style=\"text-align:center\"><nav><ul  class=\"pagination\">");
10             if (pager.PageIndex <= 1)
11             {
12                 sbHtmlText.Append("<li class=\"disabled\"><a href=\"javascript:void()\" aria-label=\"Previous\"><span aria-hidden=\"true\">&laquo;</span></a></li>");
13             }
14             else
15             {
16                 sbHtmlText.AppendFormat("<li><a href=\"javascript:loadData(1)\" aria-label=\"1\"><span aria-hidden=\"true\">&laquo;</span></a></li>", pager.PageIndex - 1);
17                 sbHtmlText.AppendFormat("<li><a href=\"javascript:loadData({0})\">{0}</a></li>", pager.PageIndex - 1);
18             }
19             sbHtmlText.AppendFormat("<li class=\"active\"><a href=\"javascript:void()\">{0}<span class=\"sr-only\">(current)</span></a></li>", pager.PageIndex);
20             if (pager.PageIndex >= pager.PageCount)
21             {
22                 sbHtmlText.Append("<li class=\"disabled\"><a href=\"javascript:void()\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>");
23             }
24             else
25             {
26                 sbHtmlText.AppendFormat("<li><a href=\"javascript:loadData({0})\">{0}</a></li>", pager.PageIndex + 1);
27                 sbHtmlText.AppendFormat("<li><a href=\"javascript:loadData({0})\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>", pager.PageIndex + 1);
28             }
29             sbHtmlText.Append("</ul></nav>");
30             sbHtmlText.AppendFormat("<div><span>每页有<strong>{0}</strong>条数据，一共有<strong>{1}</strong>页，总计<strong>{2}</strong>条数据</span></div></div>", pager.PageSize, pager.PageCount, pager.TotalCount);            
31             return MvcHtmlString.Create(sbHtmlText.ToString());
32         }
33 
34         public static MvcHtmlString Pager(this HtmlHelper helper, PagerModel pager, Func<int, string> onPageChange)
35         {
36             StringBuilder sbHtmlText = new StringBuilder();
37             sbHtmlText.Append("<div style=\"text-align:center\"><nav><ul  class=\"pagination\">");
38             if (pager.PageIndex <= 1)
39             {
40                 sbHtmlText.Append("<li class=\"disabled\"><a href=\"javascript:void()\" aria-label=\"Previous\"><span aria-hidden=\"true\">&laquo;</span></a></li>");
41             }
42             else
43             {
44                 sbHtmlText.AppendFormat("<li><a href=\"{0}\" aria-label=\"Previous\"><span aria-hidden=\"true\">&laquo;</span></a></li>", onPageChange(pager.PageIndex - 1));
45                 sbHtmlText.AppendFormat("<li><a href=\"{0}\">{1}</a></li>", onPageChange(pager.PageIndex - 1), pager.PageIndex - 1);
46             }
47             sbHtmlText.AppendFormat("<li class=\"active\"><a href=\"javascript:void()\">{0}<span class=\"sr-only\">(current)</span></a></li>", pager.PageIndex);
48             if (pager.PageIndex >= pager.PageCount)
49             {
50                 sbHtmlText.Append("<li class=\"disabled\"><a href=\"javascript:void()\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>");
51             }
52             else
53             {
54                 sbHtmlText.AppendFormat("<li><a href=\"{0}\">{1}</a></li>", onPageChange(pager.PageIndex+1),pager.PageIndex + 1);
55                 sbHtmlText.AppendFormat("<li><a href=\"{0}\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>", onPageChange(pager.PageIndex + 1));
56             }
57             sbHtmlText.Append("</ul></nav>");
58             sbHtmlText.AppendFormat("<div><span>每页有<strong>{0}</strong>条数据，一共有<strong>{1}</strong>页，总计<strong>{2}</strong>条数据</span></div></div>", pager.PageSize, pager.PageCount, pager.TotalCount);
59             return MvcHtmlString.Create(sbHtmlText.ToString());
60         }
61     }

PagerHelper

  /// <summary>
  /// PagerHelper 分页帮助类
  /// </summary>
  public static class PagerHelper
  {
      public static MvcHtmlString Pager(this HtmlHelper helper, PagerModel pager)
      {
          StringBuilder sbHtmlText = new StringBuilder();
          sbHtmlText.Append("<div style=\"text-align:center\"><nav><ul class=\"pagination\">");
          if (pager.PageIndex <= 1)
          {
              sbHtmlText.Append("<li class=\"disabled\"><a href=\"javascript:void()\" aria-label=\"Previous\"><span aria-hidden=\"true\">&laquo;</span></a></li>");
          }
          else
          {
              sbHtmlText.AppendFormat("<li><a href=\"javascript:loadData({0})\" aria-label=\"Previous\"><span aria-hidden=\"true\">&laquo;</span></a></li>", pager.PageIndex - 1);
              sbHtmlText.AppendFormat("<li><a href=\"javascript:loadData({0})\">{0}</a></li>", pager.PageIndex - 1);
          }
          sbHtmlText.AppendFormat("<li class=\"active\"><a href=\"javascript:void()\">{0}<span class=\"sr-only\">(current)</span></a></li>", pager.PageIndex);
          if (pager.PageIndex >= pager.PageCount)
          {
              sbHtmlText.Append("<li class=\"disabled\"><a href=\"javascript:void()\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>");
          }
          else
          {
              sbHtmlText.AppendFormat("<li><a href=\"javascript:loadData({0})\">{0}</a></li>", pager.PageIndex + 1);
              sbHtmlText.AppendFormat("<li><a href=\"javascript:loadData({0})\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>", pager.PageIndex + 1);
          }
          sbHtmlText.Append("</ul></nav>");
          sbHtmlText.AppendFormat("<div><span>每页有<strong>{0}</strong>条数据，一共有<strong>{1}</strong>页，总计<strong>{2}</strong>条数据</span></div></div>", pager.PageSize, pager.PageCount, pager.TotalCount);            
          return MvcHtmlString.Create(sbHtmlText.ToString());
      }
  }

利用 Func<> 简单重构了一下代码，可以自定义翻页事件

   public static MvcHtmlString Pager(this HtmlHelper helper, PagerModel pager, Func<int, string> onPageChange)
   {
       StringBuilder sbHtmlText = new StringBuilder();
       sbHtmlText.Append("<div style=\"text-align:center\"><nav><ul  class=\"pagination\">");
       if (pager.PageIndex <= 1)
       {
           sbHtmlText.Append("<li class=\"disabled\"><a href=\"javascript:void()\" aria-label=\"Previous\"><span aria-hidden=\"true\">&laquo;</span></a></li>");
       }
       else
       {
           sbHtmlText.AppendFormat("<li><a href=\"{0}\" aria-label=\"Previous\"><span aria-hidden=\"true\">&laquo;</span></a></li>", onPageChange(pager.PageIndex - 1));
           sbHtmlText.AppendFormat("<li><a href=\"{0}\">{1}</a></li>", onPageChange(pager.PageIndex - 1), pager.PageIndex - 1);
       }
       sbHtmlText.AppendFormat("<li class=\"active\"><a href=\"javascript:void()\">{0}<span class=\"sr-only\">(current)</span></a></li>", pager.PageIndex);
       if (pager.PageIndex >= pager.PageCount)
       {
           sbHtmlText.Append("<li class=\"disabled\"><a href=\"javascript:void()\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>");
       }
       else
       {
           sbHtmlText.AppendFormat("<li><a href=\"{0}\">{1}</a></li>", onPageChange(pager.PageIndex+1),pager.PageIndex + 1);
           sbHtmlText.AppendFormat("<li><a href=\"{0}\" aria-label=\"Next\"><span aria-hidden=\"true\">&raquo;</span></a></li>", onPageChange(pager.PageIndex + 1));
       }
       sbHtmlText.Append("</ul></nav>");
       sbHtmlText.AppendFormat("<div><span>每页有<strong>{0}</strong>条数据，一共有<strong>{1}</strong>页，总计<strong>{2}</strong>条数据</span></div></div>", pager.PageSize, pager.PageCount, pager.TotalCount);
       return MvcHtmlString.Create(sbHtmlText.ToString());
   }

关于样式修改维护的问题，找到一种解决方案，可以将分页代码的样式封装在一个分部视图partial，在需要分页的页面视图，引用这个分部视图并且将分页模型信息 PagerModel 传递给这个分部视图

PagedListModel 分页数据模型

PagedListModel 用来封装返回到视图 View 的数据和分页模型 PagerModel，实现代码如下

 1     /// <summary>
 2     /// 数据分页模型
 3     /// </summary>
 4     /// <typeparam name="T">数据类型</typeparam>
 5     public class PagedListModel<T> where T : class, new()
 6     {
 7         public List<T> Data { get; set; }
 8 
 9         public PagerModel Pager { get; set; }
10     }

PagedListModel

  public class PagedListModel<T> where T : class, new()
  {
      public List<T> Data { get; set; }

      public PagerModel Pager { get; set; }
  }

控制器数据处理

控制器处理代码如下：
search 是一个包含了 PageIndex 和 PageSize 的请求参数

 1             int rowsCount = 0;
 2             try
 3             {
 4                 List<Models.BlockEntity> blockList = BusinessHelper.BlockEntityHelper.GetPagedList(search.PageIndex, search.PageSize, out rowsCount, whereLambda, b => b.BlockTime, false);
 5                 PagerModel pager = new PagerModel(search.PageIndex, search.PageSize, rowsCount);
 6                 PagedListModel<Models.BlockEntity> dataList = new PagedListModel<Models.BlockEntity>() { Pager = pager, Data = blockList };
 7                 return View(dataList);
 8             }
 9             catch (Exception ex)
10             {
11                 logger.Error(ex);
12                 throw;
13             }

Controller

       int rowsCount = 0;
       try
       {
           List<Models.BlockEntity> blockList = new Business.BLLBlockEntity().GetPagedList(search.PageIndex, search.PageSize, out rowsCount, whereLambda, b => b.BlockTime, false);//记录日志
           PagerModel pager = new PagerModel(search.PageIndex, search.PageSize, rowsCount);//定义Pager Model
           PagedListModel<Models.BlockEntity> dataList = new PagedListModel<Models.BlockEntity>() { Pager = pager, Data = blockList };//定义返回到 View 的 PagedListModel
           return View(dataList);
       }
       catch (Exception ex)
       {
           logger.Error(ex);//记录日志
           throw;
       }

页面处理

首先在页面顶部声明 model 模型

  @model PagedListModel<Models.BlockEntity>

在页面上遍历数据

  @foreach (Models.BlockEntity item in Model.Data)

在需要添加分页信息的地方使用 HtmlHelper 的 Pager 扩展方法

  @Html.Pager(Model.Pager)

View代码示例

 1 @model PagedListModel<Models.BlockEntity>
 2 <table class="table table-hover">
 3     <thead>
 4         <tr>
 5             <th>黑名单类型</th>
 6             <th>黑名单内容</th>
 7             <th>拉入黑名单时间</th>
 8             <th>状态</th>
 9             <th>操作</th>
10         </tr>
11     </thead>
12     <tbody>
13         @foreach (Models.BlockEntity item in Model.Data)
14         {
15             string className = "bg-success";
16             if (!item.IsActive)
17             {
18                 className = "bg-danger";
19             }
20              <tr class="@className">
21                     <td>
22                         @item.BlockType.TypeName
23                     </td>
24                     <td>
25                         @item.BlockValue
26                     </td>
27                     <td>
28                         @item.BlockTime
29                     </td>
30                     <td>
31                         @if (item.IsActive)
32                     {
33                             <span>启用</span>
34                         }
35                         else
36                         {
37                             <span>禁用</span>
38                         }
39                     </td>
40                     <td>
41                         @if (item.IsActive)
42                     {
43                             <button type="button" class='btn btn-warning' onclick="UpdateStatus('@item.BlockId', '@item.BlockValue',-1,this)">禁用</button>
44                         }
45                         else
46                         {
47                             <button type="button" class='btn btn-warning' onclick="UpdateStatus('@item.BlockId','@item.BlockValue',1,this)">启用</button>
48                         }
49                         <button type="button" class="btn btn-danger" onclick="DeleteEntity('@item.BlockId','@item.BlockValue',this)">删除</button>
50                     </td>
51                 </tr>
52             }
53     </tbody>
54 </table>
55 @Html.Pager(Model.Pager)