Mvc分页：为IQueryable定义一个扩展方法，直接反回PagedList<T>结果集

namespace Entity
{
public interface IPagedList
{
/// <summary>
/// 记录数
/// </summary>
int TotalCount { get; set; }
/// <summary>
/// 页数
/// </summary>
int TotalPages { get; set; }
/// <summary>
/// 当前页
/// </summary>
int PageIndex { get; set; }
/// <summary>
/// 页面大小
/// </summary>
int PageSize { get; set; }
/// <summary>
/// 是否上一页
/// </summary>
bool IsPreviousPage { get; }
/// <summary>
/// 是否下一页
/// </summary>
bool IsNextPage { get; }
}
/// <summary>
/// 分页通用类
/// </summary>
/// <typeparam name="T"></typeparam>
public class PagedList<T> : List<T>, IPagedList
{
/// <summary>
/// 数据源为IQueryable的范型
/// </summary>
/// <param name="source">数据源</param>
/// <param name="index">当前页</param>
/// <param name="pageSize">每页显示多少条记录</param>
public PagedList(IQueryable<T> source, int index, int pageSize)
{
if (source != null) //判断传过来的实体集是否为空
{
int total = source.Count();
this.TotalCount = total;
this.TotalPages = total / pageSize;

if (total % pageSize > 0)
TotalPages++;

this.PageSize = pageSize;
if (index > this.TotalPages)
{
index = this.TotalPages;
}
if (index < 1)
{
index = 1;
}
this.PageIndex = index;
this.AddRange(source.Skip((index - 1) * pageSize).Take(pageSize).ToList()); //Skip是跳到第几页，Take返回多少条
}
}

/// <summary>
/// 总页数
/// </summary>
public int TotalPages { get; set; }
/// <summary>
/// 总记录数
/// </summary>
public int TotalCount { get; set; }
/// <summary>
/// 当前页
/// </summary>
public int PageIndex { get; set; }
/// <summary>
/// 每页显示多少条记录
/// </summary>
public int PageSize { get; set; }
/// <summary>
/// 是否有上一页
/// </summary>
public bool IsPreviousPage { get { return (PageIndex > 0); } }
/// <summary>
/// 是否有下一页
/// </summary>
public bool IsNextPage { get { return (PageIndex * PageSize) <= TotalCount; } }

private NameValueCollection _AddParameters = new NameValueCollection();
/// <summary>
/// 分页参数
/// </summary>
public NameValueCollection AddParameters
{
get { return _AddParameters; }
set { _AddParameters = value; }
}

}

/// <summary>
/// PagedList扩展类
/// </summary>
public static class ExtendPagedList
{
/// <summary>
/// 返回PagedList<T>类型的IQueryable的扩展方法
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="linq"></param>
/// <param name="pageIndex"></param>
/// <param name="pageSize"></param>
/// <returns></returns>
public static PagedList<T> ToPagedList<T>(this IQueryable<T> linq, int pageIndex, int pageSize)
{
return new PagedList<T>(linq, pageIndex, pageSize);
}
}
}