08 April 2008 ASP.NET MVC, Paging, User Controls robert.muehsig Edit

Each website, content management system, blog and so on need "pagination". A never ending site with "foo-entries" is not very professional. Thats why i created for my ASP.NET MVC sample (a kigg / dotnetnuke similar page) a specific"Pagination View User Control"

In almost every "List" View I implemented my control:

image

image

The advantages of such an control:

- look and feel is on each page the same 
- changes are very easy to implement

In my sampel I use this CSS design.

Structure

image 

A typical MVC View User Control

Code

Pagination.ascx

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="Pagination.ascx.cs" Inherits="Mvc2.Views.Shared.Pagination" %>
<ul class="pagination-clean">
    <% if (ViewData.HasPreviousPage)
        { %>
          <li class="previous"><a href="<%=ViewData.PageActionLink.Replace("%7Bpage%7D", (ViewData.PageIndex - 1).ToString())%>">« Previous</a></li>
     <% }
       else
        { %>
          <li class="previous-off">« Previous</li>
     <% } %>
                  
     <%for (int page = 1; page <= ViewData.TotalPages; page++)
        { 
        if (page == ViewData.PageIndex)
            { %>
              <li class="active"><%=page.ToString()%></li>
         <% }
        else
            { %>
              <li><a href="<%=ViewData.PageActionLink.Replace("%7Bpage%7D", page.ToString())%>"><%=page.ToString()%></a></li>
         <% }
        } 
              
       if (ViewData.HasNextPage)
            { %>
              <li class="next"><a href="<%=ViewData.PageActionLink.Replace("%7Bpage%7D", (ViewData.PageIndex + 1).ToString())%>">Next »</a></li>
         <% }
       else
            { %>
               <li class="next-off">Next »</li>
         <% } %>
</ul> 

Pagination.ascx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace Mvc2.Views.Shared
{
    public class PaginationViewData
    {
        public int PageIndex { get; set; }
        public int TotalPages { get; set; }
        public int PageSize { get; set; }
        public int TotalCount { get; set; }
        public string PageActionLink { get; set; }
        public bool HasPreviousPage
        {
            get
            {
                return (PageIndex > 1);
            }
        }

        public bool HasNextPage
        {
            get
            {
                return (PageIndex * PageSize) <= TotalCount;
            }
        }
    }

    public partial class Pagination : System.Web.Mvc.ViewUserControl<PaginationViewData>
    {
        public Pagination()
        {

        }
    }
}

The ViewData is strongly typed by the PaginationViewData class.

How to use - Helper "PagedList"

It is very easy to use, if you are already use the PageList class:

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Collections.Generic;

namespace Mvc2.Helpers
{
    public class PagedList<T> : List<T>
    {
        public PagedList(IQueryable<T> source, int index, int pageSize)
        {
            this.TotalCount = source.Count();
            this.PageSize = pageSize;
            this.PageIndex = index;
            this.AddRange(source.Skip((index - 1) * pageSize).Take(pageSize).ToList());

            int pageResult = 0;
            for (int counter = 1; pageResult < this.TotalCount; counter++)
            {
                pageResult = counter * this.PageSize;
                this.TotalPages = counter;
            }
        }

        public int TotalPages
        {
            get;
            set;
        }

        public int TotalCount
        {
            get;
            set;
        }

        public int PageIndex
        {
            get;
            set;
        }

        public int PageSize
        {
            get;
            set;
        }

        public bool HasPreviousPage
        {
            get
            {
                return (PageIndex > 1);
            }
        }

        public bool HasNextPage
        {
            get
            {
                return (PageIndex * PageSize) <= TotalCount;
            }
        }
    }

    public static class Pagination
    {
        public static PagedList<T> ToPagedList<T>(this IQueryable<T> source, int index, int pageSize)
        {
            return new PagedList<T>(source, index, pageSize);
        }

        public static PagedList<T> ToPagedList<T>(this IQueryable<T> source, int index)
        {
            return new PagedList<T>(source, index, 10);
        }
    }
}

The original code wrote Rob Conery - in my version is the first page the number 1, not 0 - a user could confused by the link to page number 0 ;)

How to use- in the view page

I render the control by using the in-build "Html.RenderUserControl" helper:

    <%=Html.RenderUserControl("~/Views/Shared/Pagination.ascx", new Mvc2.Views.Shared.PaginationViewData()
      {
          PageIndex = ViewData.EntryList.PageIndex,
          TotalPages = ViewData.EntryList.TotalPages,
          PageActionLink = Url.Action("List","Entry", new { category = ViewData.Category, page = "{page}"}),
          TotalCount = ViewData.EntryList.TotalCount,
          PageSize = ViewData.EntryList.PageSize
      }, null)%>
	  

The properties of the control and of the PagedList are almost the same - only the "PageActionLink" is a specific property. The "PageActionLink" is the action Link to your controller - "/Management/Tag/2" route to your "Management"-Controller and "Tag"-ActionMethod with the page parameter. The "page = {page}" parameter is only a template for the real page number, which will be replaced in my control:

<li><a href="<%=ViewData.PageActionLink.Replace("%7Bpage%7D", page.ToString())%>"><%=page.ToString()%></a></li>

The URL helper method encode the { and } to %7B and %7D. I can´t explain it very well in english - one quick look in the source code (pagination.ascx) is very helpful ;)

Feel free to use it.

PS: English blogging is hard :/ ;)


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