关于分页的问题

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
//using System.Xml.Linq;
using System.Data.OleDb;
using PracticeMyBookShopBLL;
using PracticeMyBookShopModels;

public partial class xwdt : System.Web.UI.Page
{
    OleDbConnection cn = new OleDbConnection(System.Configuration.ConfigurationManager.AppSettings["SQLConnString"].ToString());
    int shuliang;
    protected void Page_Load(object sender, EventArgs e)
    {

        if (!IsPostBack)
        {

            bb();
            aa();
            Label1.Text = shuliang.ToString();
            ViewState["Page"] = 0;
        }
        Databind();
    }
    public void bb()
    {

        OleDbDataAdapter da = new OleDbDataAdapter("select title,fbsj from hangye ", cn);
        DataSet ds = new DataSet();
        da.Fill(ds);
        GridView1.DataSourceID = null;
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind();

    }
    public int aa()
    {
        string str = "select count(id) as ID from hangye";
        cn.Open();
        OleDbCommand com = new OleDbCommand(str, cn);
        int set = com.ExecuteNonQuery();
        cn.Close();
        return set;

    }
    private void Databind()
    {
        PagedDataSource pdsList = new PagedDataSource();
        pdsList.DataSource = BookManager.GetHotBooks();
        pdsList.AllowPaging = true;
        pdsList.PageSize = 5;
        pdsList.CurrentPageIndex = Pager;
        lblCurrentPage.Text = "第 " + (pdsList.CurrentPageIndex + 1).ToString() + " 页 共 " + pdsList.PageCount.ToString() + " 页";
        SetEnablE(pdsList);
        dlBooks.DataSource = pdsList;
        dlBooks.DataBind();
    }
    private void SetEnable(PagedDataSource pds)
    {
        lnkbtnPre.Enabled = true;
        lnkbtnNext.Enabled = true;
        if (pds.IsFirstPage)
        {
            lnkbtnPre.Enabled = false;
        }
        if (pds.IsLastPage)
            lnkbtnNext.Enabled = false;
    }
    private int Pager
    {
        get{ return (int)ViewState["Page"]; }
        set { ViewState["Page"] = value; }
    }
    protected void lnkBtnPre_Click(object sender, EventArgs e)
    {
        Pager--;
        Databind();
    }
    protected void lnkbtnNext_Click(object sender, EventArgs e)
    {
        Pager++;
        Databind();
    }
}