private void UpdateBalance()
        {
            int i;
            int account;
            int qty;
            int price;

            for (i = 1; i < (CGVIEW.Rows.Count - 1);i++)
            {
                qty = 0;
                price = 0;
                account = int.Parse(CGVIEW.Rows[i - 1].Cells["ACCOUNT"].Value.ToString());

                if (CGVIEW.Rows[i].Cells["QTY"].Value != null)
                {
                    if (CGVIEW.Rows[i].Cells["QTY"].Value.ToString().Length != 0)
                    {
                        qty = int.Parse(CGVIEW.Rows[i].Cells["QTY"].Value.ToString());
                    }
                }

                if (CGVIEW.Rows[i].Cells["PRICE"].Value != null)
                {
                    if (CGVIEW.Rows[i].Cells["PRICE"].Value.ToString().Length != 0)
                    {
                        price = int.Parse(CGVIEW.Rows[i].Cells["PRICE"].Value.ToString());
                    }
                }
                CGVIEW.Rows[i].Cells["ACCOUNT"].Value =(qty*price).ToString();
            }
        }

        private void CGVIEW_CellValueChanged(object sender, DataGridViewCellEventArgs e)
        {
            UpdateBalance();
        }