PagedList.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.Collections.Generic;
using System.Linq;

namespace Everest.Library.Mvc.Paging{
  public class PagedList<T> : List<T>, IPagedList<T>
  {
    public PagedList(IEnumerable<T> source, int index, int pageSize) : this(source, index, pageSize, null)
    {
    }

    public PagedList(IEnumerable<T> source, int index, int pageSize, int? totalCount)
    {
      Initialize(source.AsQueryable(), index, pageSize, totalCount);
    }

    public PagedList(IQueryable<T> source, int index, int pageSize) : this(source, index, pageSize, null)
    {
    }

    public PagedList(IQueryable<T> source, int index, int pageSize, int? totalCount)
    {
      Initialize(source, index, pageSize, totalCount);
    }

    #region IPagedList Members

    public int PageCount { get; private set; }
    public int TotalItemCount { get; private set; }
    public int PageIndex { get; private set; }
    public int PageNumber { get { return PageIndex + 1; } }
    public int PageSize { get; private set; }
    public bool HasPreviousPage { get; private set; }
    public bool HasNextPage { get; private set; }
    public bool IsFirstPage { get; private set; }
    public bool IsLastPage { get; private set; }

    #endregion

    protected void Initialize(IQueryable<T> source, int index, int pageSize, int? totalCount)
    {
      //### argument checking
      if (index < 0)
      {
        throw new ArgumentOutOfRangeException("PageIndex cannot be below 0.");
      }
      if (pageSize < 1)
      {
        throw new ArgumentOutOfRangeException("PageSize cannot be less than 1.");
      }

      //### set source to blank list if source is null to prevent exceptions
      if (source == null)
      {
        source = new List<T>().AsQueryable();
      }

      //### set properties
      if (!totalCount.HasValue)
      {
        TotalItemCount = source.Count();
      }
      PageSize = pageSize;
      PageIndex = index;
      if (TotalItemCount > 0)
      {
        PageCount = (int)Math.Ceiling(TotalItemCount / (double)PageSize);
      }
      else
      {
        PageCount = 0;
      }
      HasPreviousPage = (PageIndex > 0);
      HasNextPage = (PageIndex < (PageCount - 1));
      IsFirstPage = (PageIndex <= 0);
      IsLastPage = (PageIndex >= (PageCount - 1));

      //### add items to internal list
      if (TotalItemCount > 0)
      {
        AddRange(source.Skip((index) * pageSize).Take(pageSize).ToList());
      }
    }
  }
}