Upload an excel sheet data

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;

namespace Retrieving_excel_data_to_combobox
{
    public partial class Form1 : Form
    {
        public OleDbConnection con;
        public void pintu(string s)
        {
            con = new OleDbConnection("provider=Microsoft.Jet.OLEDB.4.0; " + "data source='" + s + " '; " + "Extended Properties=Excel 8.0;");

        }
        public OleDbCommand com;
        public DataSet ds;
        public OleDbDataAdapter oledbda;
        public DataTable dt;
        public string str;

        public Form1()
        {
            InitializeComponent();
        }

        private void btnbrowse_Click(object sender, EventArgs e)
        {
            OpenFileDialog openfiledialog1 = new OpenFileDialog();
            openfiledialog1.ShowDialog();
            openfiledialog1.Filter = "allfiles|*.xls";
            TextBox1.Text = openfiledialog1.FileName;

        }

       

        private void btndisplay_Click(object sender, EventArgs e)
        {
            pintu(TextBox1.Text);
            try
            {
                con.Open();
                str = "select * from [sheet1$]";
                com = new OleDbCommand(str, con);
                ds = new DataSet();
                oledbda = new OleDbDataAdapter(com);
                oledbda.Fill(ds, "[sheet1$]");
                con.Close();
                DataGridView1.DataSource = ds;
                DataGridView1.DataMember = "[sheet1$]";
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

        }
    }
}

I got the answer guys..