IList<T>绑定到GridView上面的分页问题~~~~在线等候

这个是后台代码
public   partial   class   Controls_BookList   :   System.Web.UI.UserControl
{
IList <BookInfo>   dataSource;
string   categoryId;
protected   void   Page_Load   (   object   sender   ,   EventArgs   e   )
{
if   (   !Page.IsPostBack   )
{
BindData   (   );
}
}
private   void   BindData   (   )
{
Book   book=new   Book   (   );  
categoryId=Request.QueryString   [   "categoryId "   ];
dataSource=book.GetProductsByCategory   (   categoryId   );
this.BookListView.DataSource=dataSource   as   List <BookInfo> ;
this.BookListView.DataBind   (   );
}protected   void   BookListView_PageIndexChanging   (   object   sender   ,   GridViewPageEventArgs   e   )
{
BookListView.PageIndex=e.NewPageIndex;
BindData   (   );
}
}
这个是前台代码.<div   id= "BookListControl ">
        <asp:GridView   ID= "BookListView "   runat= "server "   Width= "508px "     OnPageIndexChanging= "BookListView_PageIndexChanging "   AllowPaging= "True "   PageSize= "2 "   AutoGenerateColumns= "False "   EnableTheming= "False "   EnableViewState= "False ">
                <Columns>
                <asp:TemplateField>
                        <ItemTemplate>  
                                <div   class= "BookListClass "   style= "width:508px; ">
                                        <div   class= "BookName "> <%#   Eval( "BookName ")   %> </div>
                                        <img     alt= ' <%#   Eval( "BookName ")   %> '   src= '   <%#   string.Format( "/Web/Image/{0}.jpg ",Eval( "BookId ").ToString().Replace( "   ", " "))%> '       width= "160px "   height= "200px "/>
                                        <div   class= "AuthorName1 "> 作者: </div> <div   class= "AuthorName2 "> <%#   Eval( "AuthorName ")   %> </div>
                                        <div   class= "PublishDate1 "> 出版日期: </div> <div   class= "PublishDate2 "> <%#   Eval( "PublishDate ")   %> </div>
                                        <div   class= "Price1 "> 市场价: </div> <div   class= "Price2 "> <%#   Eval( "Price ")   %> </div>
                                        <div   class= "MyPrice1 "> MyPrice: </div> <div   class= "MyPrice2 "> <%#   Eval( "MyPrice ")   %> </div>
                                </div>  
                        </ItemTemplate>
                </asp:TemplateField>
                </Columns>
        </asp:GridView>
  </div>或者你也可以不用这个,只要实现了IList <T> 绑定到GridView上面分页就行了~~~~
先谢谢了
我这个代码可以分页,但是点到第二页之后就回不到第一页了.......