Pager.cs :  » Content-Management-Systems-CMS » Kooboo » Everest » Library » Mvc » Paging » C# / CSharp Open Source

/*
Kooboo is a content management system based on ASP.NET MVC framework. Copyright 2009 Yardi Technology Limited.

This program is free software: you can redistribute it and/or modify it under the terms of the
GNU General Public License version 3 as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program.
If not, see http://www.kooboo.com/gpl3/.
*/
using System;
using System.Text;
using System.Web.Mvc;
using System.Web.Routing;

namespace Everest.Library.Mvc.Paging{
    public class Pager
    {
        const string pageIndexName = "pageIndex";
        protected ViewContext viewContext;
        private readonly int pageSize;
        private readonly int currentPage;
        private readonly int totalItemCount;
        protected readonly RouteValueDictionary routeValues;
        private RouteCollection routeTable;

        public Pager(ViewContext viewContext, int pageSize, int currentPage, int totalItemCount, RouteValueDictionary valuesDictionary)
            : this(viewContext, pageSize, currentPage, totalItemCount, valuesDictionary, RouteTable.Routes)
        {
        }
        public Pager(ViewContext viewContext, int pageSize, int currentPage, int totalItemCount, RouteValueDictionary valuesDictionary, RouteCollection routeTable)
        {
            this.viewContext = viewContext;
            this.pageSize = pageSize;
            this.currentPage = currentPage;
            this.totalItemCount = totalItemCount;
            this.routeValues = valuesDictionary;
            this.routeTable = routeTable;
        }

        public string RenderHtml()
        {
            int pageCount = (int)Math.Ceiling(this.totalItemCount / (double)this.pageSize);
            int nrOfPagesToDisplay = 10;
            if (totalItemCount == 0 || pageCount == 1)
            {
                return "";
            }
            var sb = new StringBuilder(@"<div class=""pager"">");

            // Previous
            if (this.currentPage > 1)
            {
                sb.Append(GeneratePageLink("&lt;", this.currentPage - 1));
            }
            else
            {
                sb.Append("<span class=\"disabled\">&lt;</span>");
            }

            int start = 1;
            int end = pageCount;

            if (pageCount > nrOfPagesToDisplay)
            {
                int middle = (int)Math.Ceiling(nrOfPagesToDisplay / 2d) - 1;
                int below = (this.currentPage - middle);
                int above = (this.currentPage + middle);

                if (below < 4)
                {
                    above = nrOfPagesToDisplay;
                    below = 1;
                }
                else if (above > (pageCount - 4))
                {
                    above = pageCount;
                    below = (pageCount - nrOfPagesToDisplay);
                }

                start = below;
                end = above;
            }

            if (start > 3)
            {
                sb.Append(GeneratePageLink("1", 1));
                sb.Append(GeneratePageLink("2", 2));
                sb.Append("...");
            }
            for (int i = start; i <= end; i++)
            {
                if (i == this.currentPage)
                {
                    sb.AppendFormat("<span class=\"current\">{0}</span>", i);
                }
                else
                {
                    sb.Append(GeneratePageLink(i.ToString(), i));
                }
            }
            if (end < (pageCount - 3))
            {
                sb.Append("...");
                sb.Append(GeneratePageLink((pageCount - 1).ToString(), pageCount - 1));
                sb.Append(GeneratePageLink(pageCount.ToString(), pageCount));
            }

            // Next
            if (this.currentPage < pageCount)
            {
                sb.Append(GeneratePageLink("&gt;", (this.currentPage + 1)));
            }
            else
            {
                sb.Append("<span class=\"disabled\">&gt;</span>");
            }
            sb.Append("</div>");
            return sb.ToString();
        }

        protected virtual string GeneratePageLink(string linkText, int pageNumber)
        {
            var pageLinkValueDictionary = new RouteValueDictionary(this.routeValues);
            pageLinkValueDictionary.Add(pageIndexName, pageNumber);

            //var virtualPathData = this.viewContext.RouteData.Route.GetVirtualPath(this.viewContext, pageLinkValueDictionary);
            var virtualPathData = routeTable.GetVirtualPath(this.viewContext.RequestContext, pageLinkValueDictionary);

            if (virtualPathData != null)
            {
                string linkFormat = "<a href=\"{0}\">{1}</a>";
                return String.Format(linkFormat, virtualPathData.VirtualPath, linkText);
            }
            else
            {
                return null;
            }
        }
    }
}