Paging With DropDownList in ASP.NET

Default.aspx.cs code

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.SqlClient;
namespace Paging_with_dropdownlist
{
public partial class _Default : System.Web.UI.Page
{
string connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
SqlCommand com;
SqlDataAdapter sqlda;
DataSet ds;
string str;
int size = 0;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DropDownList1.Items.Insert(0, ("Select"));
}
}
void bindgrid()
{
SqlConnection con = new SqlConnection(connStr);
con.Open();
str = "select * from employee";
com = new SqlCommand(str, con);
sqlda = new SqlDataAdapter(com);
ds = new DataSet();
sqlda.Fill(ds, "employee");
g1.DataMember = "employee";
g1.DataSource = ds;
g1.DataBind();
con.Close();
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
if (DropDownList1.SelectedItem.Text != "0")
{
size = int.Parse(DropDownList1.SelectedItem.Value.ToString());
g1.PageSize = size;
bindgrid();
}
}
protected void g1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
g1.PageIndex = e.NewPageIndex;
bindgrid();
}
}
}

Output