how to retrive the database values

Perhaps something like this...

using System.Data.OleDb;
using System.Data;
namepsace whatever
{
  public partial class MainForm : Form
  {
  public MainForm()
  {
  InitializeComponent();
  this.WindowState = FormWindowState.Maximized; 
  myCon = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data 
Source=C:\...databasename.mdb");
  }
  OleDbConnection myCon;
  OleDbCommand cmd;
  OleDbDataAdapter adapter;
  DataSet ds;



 private void btnGetData_Click(object sender, EventArgs e)
  {
  adapter = new OleDbDataAdapter("select * from SomeTableName", myCon);
  ds = new DataSet();
  adapter.Fill(ds, "TableName");
  adapter.Update(ds, "TableName");
  txtID.Text = ds.Tables[0].Rows[rno][0].ToString();
  CBTitle.Text = ds.Tables[0].Rows[rno][2].ToString();
  }
}

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 Insert_Update_Delete_DataGridView
{
    public partial class Form1 : Form
    {
        string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["dsn"];
        OleDbCommand com;
        OleDbDataAdapter oledbda;
        string str;
        DataSet ds;
  
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            bindgrid();
        }
        private void bindgrid()
        {
            OleDbConnection con = new OleDbConnection(ConnectionString);
            con.Open();
            str = "select * from employee";
            com = new OleDbCommand(str, con);
            oledbda = new OleDbDataAdapter(com);
            ds = new DataSet();
            oledbda.Fill(ds, "employee");
            dataGridView1.DataMember="employee";
            dataGridView1.DataSource = ds;
            con.Close();
        }
}