Custom paging with ASP.NET GridView

///Auther:    Tanweer Akhtar
///Date:      26-06-2012
///Email:     tanweer_bravi@yahoo.com
///License    Copyright@tanweerbravi
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI.HtmlControls;
using System.Collections;
using System.Configuration;
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        int size = 0; int index = 0;

        if (!Page.IsPostBack)
        {
            //set the page size and current page number here, default is 10 and 1 respectively
            size = string.IsNullOrEmpty(Request["Size"]) ? 10 : Convert.ToInt32(Request["Size"]);
            index = string.IsNullOrEmpty(Request["Index"]) ? 1 : Convert.ToInt32(Request["Index"]);
            //load data from database
            BindGrid(size, index);

            //////////////////////////////////////////////////////
            if (size == 10)
                A1.Attributes.Add("class", "page-numbers current");
            else if(size==15)
                A2.Attributes.Add("class", "page-numbers current");
        }
    }
    void BindGrid(int size, int index)
    {
        //page url--get from Web.config file--------change it as your page URL
        string url = ConfigurationManager.AppSettings["URL"].ToString();
        //string templates for links
        string link = "<a  href='" + url + "?Index=##Index##&amp;Size=##Size##'><span class='page-numbers'>##Text##</span></a>";
        string link_pre = "<a href='" + url + "?Index=##Index##&amp;Size=##Size##'><span class='page-numbers prev'>##Text##</span></a>";
        string link_next = "<a href='" + url + "?Index=##Index##&amp;Size=##Size##'><span class='page-numbers next'>##Text##</span></a>";
        try
        {
            //the connectionstring from Web.config file--------change it as per your database settings
            String ConnStr = ConfigurationManager.ConnectionStrings["myConnection"].ToString();
            //the sql query with paging logics
            //here table name is "Orders" change this name as your requirement.
            //"CustomerID" is the column by which you can sort the records, change it as per your requirement
            String SQL = @"select * from (SELECT  ROW_NUMBER() OVER (ORDER BY CustomerID asc) as row,* FROM Orders) tblTemp
                        WHERE row between (" + index + " - 1) * " + size + " + 1 and " + index + "*" + size + " ";
            SQL += " select COUNT(*) from Orders";
            //fetching data from database suing SqlDataAdapter Fill method to bind the Gridview
            SqlDataAdapter ad = new SqlDataAdapter(SQL, ConnStr);
            DataSet ds = new DataSet();
            ad.Fill(ds);
            //bind the grid with the ist data table---------remember that this dataset consist of two data tables
            this.gvPaging.DataSource = ds.Tables[0];
            this.gvPaging.DataBind();
            ////////get the n number of record///////////
            Double n = Convert.ToDouble(Convert.ToInt32(ds.Tables[1].Rows[0][0]) / size);
            /////////setting page numbers with links
            if (index != 1)
                lblpre.Text = link_pre.Replace("##Size##", size.ToString()).Replace("##Index##", (index - 1).ToString()).Replace("##Text##", "prev");
            else
                lblpre.Text = "<span class='page-numbers prev'>prev</span>";
            if (index != Convert.ToInt32(n))
                lblnext.Text = link_next.Replace("##Size##", size.ToString()).Replace("##Index##", (index + 1).ToString()).Replace("##Text##", "next");
            else
                lblnext.Text = "<span class='page-numbers next'>next</span>";
            //generate dynamic paging 
            int start;
            if (index <= 5) start = 1;
            else start = index - 4;
            for (int i = start; i < start + 7; i++)
            {
                if (i > n) continue;
                //create dynamic HyperLinks 
                HyperLink lnk = new HyperLink();

                lnk.ID = "lnk_" + i.ToString();
                if (i == index)//current page
                {
                    lnk.CssClass = "page-numbers current";
                    lnk.Text = i.ToString();
                }
                else
                {
                    lnk.Text = i.ToString();
                    lnk.CssClass = "page-numbers";
                    lnk.NavigateUrl = url + "?Index=" + i + "&Size=" + size + "";
                }
                //add links to page
                this.pl.Controls.Add(lnk);
            }
            //------------------------------------------------------------------
            //set up the ist page and the last page
            if (n > 7)
            {
                if (index <= Convert.ToInt32(n / 2))
                {
                    lblLast.Visible = true;
                    lblIst.Visible = false;
                    lblLast.Text = link.Replace("##Index##", n.ToString()).Replace("##Size##", size.ToString()).Replace("##Text##", n.ToString());
                    spDot2.Visible = true;
                    spDot1.Visible = false;
                }
                else
                {
                    lblLast.Visible = false;
                    lblIst.Visible = true;
                    lblIst.Text = link.Replace("##Index##", (n - n + 1).ToString()).Replace("##Size##", size.ToString()).Replace("##Text##", (n - n + 1).ToString());
                    spDot2.Visible = false;
                    spDot1.Visible = true;
                }
            }
        }
        catch (Exception ee)
        {
            //catch the exception
        }
    }


}