private void btnCapPhatLenh_Click(object sender, EventArgs e)
        {
            if (txtMaCapLenh.Text != null)
            {
                DateTime date = DateTime.Now;
                connection.CapLenhXuatBen(txtMaCapLenh.Text, DateTime.Now.ToString());

                LoadCapLenh();
            }
            else
            {
                MessageBox.Show("Chua xac dinh xe duoc cap phat");
            }
        }