how to show the data in grid view ( or any tool to view)

how to show the data in grid view ( or any tool to view data one by one after put the barcode is in textbox i need to show the data in grid after the data is shown ) i need to clear (textbox)after the data are shown in the grid view .again i enter the barcode in the (textbox) i need to show the previous data + current data

using asp.net c# language

if i put barcode as 1000 in textbox i need the data from sql server and show in a gridview or any tool then am going to put 1001 so i need to clear the textbox and now i need the 1000 and 1001 datas shown in the gridview or any tool to show

this is my design

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="gridview.aspx.cs" Inherits="gridview" %>

Untitled Page

	ontextchanged="TextBox1_TextChanged">

this is my 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;

public partial class gridview : System.Web.UI.Page

{

DataSet ds = new DataSet();

SqlDataAdapter sda;

SqlConnection con;

protected void Page_Load(object sender, EventArgs e)

{

con = new SqlConnection("Data Source=SELVI-PC\\SQLEXPRESS;Initial Catalog=demo;Persist Security Info=True;Integrated Security=True");

if (!IsPostBack)

{

//TextBox1.Text = ds.Tables[0].Rows[0]["barcode"].ToString();

}

protected void TextBox1_TextChanged(object sender, EventArgs e)

{

if (TextBox1.Text != "")

{

SqlCommand cmd = new SqlCommand("select * from purchase where barcode="+TextBox1.Text, con);

sda = new SqlDataAdapter(cmd);

sda.Fill(ds);

GridView1.DataSource = ds;

GridView1.DataBind();

}