update Acess2003 database

private void panel4_Click(object sender, EventArgs e)
        {

            try 
            {
                


                OleDbDataAdapter adpt = new OleDbDataAdapter("select Stu_name as 'Name' ,Stu_class as 'Class',Stu_roll as 'Roll Number',Stu_section as 'Section',Attendence from EnrollStud where Stu_class='" + comboBox3.SelectedItem + "' and Stu_section='" + comboBox4.SelectedItem + "'", conn);
                conn.Open();

                OleDbCommandBuilder cdb = new OleDbCommandBuilder(adpt);
                
                adpt.Fill(ds);
                adpt.Fill(dt);
                ds.Tables[0];
                a = dt.Rows.Count;
                
                if (dt.Rows.Count.Equals(0))
                {
                    MessageBox.Show("Sorry!Please Select Correct Class and section");

                }
                else
                {
                    dataGridView1.DataSource =dt;
}
                conn.Close();
}

on save button click i want to update changes of gridview into acess database

private void button1_Click(object sender, EventArgs e)
        {

        try
            {
                if (dataGridView1.Rows.Count.Equals(0))
                {
                    MessageBox.Show("select some data!!","message",MessageBoxButtons.OK,MessageBoxIcon.Stop);

                }
                else
                {
                    adpt.Update(dt);

                    MessageBox.Show("Record is updated", "message", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            
            }
            

        }


I am using acess2003 as database