1:  public interface IRepository<T, TPkType>
   2:  {
   3:      IQueryable<T> Select();
   4:      T SelectOnId(TPkType id);
   5:      IQueryable<T> SelectPaged<TResult>(int pageIndex, int pageSize, Expression<Func<T, TResult>> sortExpression, bool isAscending);
   6:      IQueryable<T> FindPaged<TResult>(int pageIndex, int pageSize, Expression<Func<T, bool>> findExpression, Expression<Func<T, TResult>> sortExpression, bool isAscending);
   7:      IQueryable<T> Find(Expression<Func<T, bool>> expression);
   8:      T Save(T item);
   9:      void Delete(TPkType id);
  10:  }
  11:   
  12:  public interface IPagedList<T> : IList<T>
  13:  {
  14:      int PageCount { get; }
  15:      int TotalItemCount { get; }
  16:      int PageIndex { get; }
  17:      int PageNumber { get; }
  18:      int PageSize { get; }
  19:      bool HasPreviousPage { get; }
  20:      bool HasNextPage { get; }
  21:      bool IsFirstPage { get; }
  22:      bool IsLastPage { get; }
  23:  }
  24:   
  25:  public class SortedPagedList<T, TResult> : List<T>, IPagedList<T>
  26:  {
  27:      public int PageCount { get; private set; }
  28:      public int TotalItemCount { get; private set; }
  29:      public int PageIndex { get; private set; }
  30:      public int PageNumber { get { return PageIndex + 1; } }
  31:      public int PageSize { get; private set; }
  32:      public bool HasPreviousPage { get; private set; }
  33:      public bool HasNextPage { get; private set; }
  34:      public bool IsFirstPage { get; private set; }
  35:      public bool IsLastPage { get; private set; }
  36:   
  37:      public SortedPagedList(IEnumerable<T> source, int index, int pageSize, Expression<Func<T, TResult>> keySelector, bool asc)
  38:      {
  39:          if (source is IQueryable<T>)
  40:          {
  41:              Initialize(source as IQueryable<T>, index, pageSize, keySelector, asc);
  42:          }
  43:          else
  44:          {
  45:              Initialize(source.AsQueryable(), index, pageSize, keySelector, asc);
  46:          }
  47:      }
  48:   
  49:      public SortedPagedList(IQueryable<T> source, int index, int pageSize, Expression<Func<T, TResult>> keySelector, bool asc)
  50:      {
  51:          Initialize(source, index, pageSize, keySelector, asc);
  52:      }
  53:   
  54:      protected void Initialize(IQueryable<T> source, int index, int pageSize, Expression<Func<T, TResult>> keySelector, bool asc)
  55:      {
  56:          if (source == null)
  57:          {
  58:              source = new List<T>().AsQueryable();
  59:          }
  60:   
  61:          TotalItemCount = source.Count();
  62:          PageSize = pageSize;
  63:          PageIndex = index;
  64:   
  65:          if (TotalItemCount > 0)
  66:          {
  67:              PageCount = (int)Math.Ceiling(TotalItemCount / (double)PageSize);
  68:          }
  69:          else
  70:          {
  71:              PageCount = 0;
  72:          }
  73:   
  74:          HasPreviousPage = (PageIndex > 0);
  75:          HasNextPage = (PageIndex < (PageCount - 1));
  76:          IsFirstPage = (PageIndex <= 0);
  77:          IsLastPage = (PageIndex >= (PageCount - 1));
  78:   
  79:          if (index < 0)
  80:          {
  81:              throw new ArgumentOutOfRangeException("index", "PageIndex cannot be below 0.");
  82:          }
  83:          if (pageSize < 1)
  84:          {
  85:              throw new ArgumentOutOfRangeException("pageSize", "PageSize cannot be less than 1.");
  86:          }
  87:   
  88:          if (TotalItemCount > 0)
  89:          {
  90:              if (asc)
  91:              {
  92:                  AddRange(source.OrderBy(keySelector).Skip(index * pageSize).Take(pageSize));
  93:              }
  94:              else
  95:              {
  96:                  AddRange(source.OrderByDescending(keySelector).Skip(index * pageSize).Take(pageSize));
  97:              }
  98:          }
  99:      }
 100:  }
 101:   
 102:  public static class Pagination
 103:  {
 104:      public static SortedPagedList<T, TResult> ToPagedList<T, TResult>(this IQueryable<T> source, int index, int pageSize, Expression<Func<T, TResult>> keySelector, bool asc)
 105:      {
 106:          return new SortedPagedList<T, TResult>(source, index, pageSize, keySelector, asc);
 107:      }
 108:   
 109:      public static SortedPagedList<T, TResult> ToPagedList<T, TResult>(this IEnumerable<T> source, int index, int pageSize, Expression<Func<T, TResult>> keySelector, bool asc)
 110:      {
 111:          return new SortedPagedList<T, TResult>(source, index, pageSize, keySelector, asc);
 112:      }
 113:  }