private void billitemgrid_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            DataGridViewRow r = new DataGridViewRow();

            r = billitemgrid.Rows[e.RowIndex];
            if (DialogResult.Yes == MessageBox.Show("Are you want to Delete", "Delete", MessageBoxButtons.YesNo, MessageBoxIcon.Information))
            {
                billgrid b = billsitem.FirstOrDefault(m => m.Stockid == Int32.Parse(r.Cells["Stockid"].Value.ToString()) && m.Quantity == Int32.Parse(r.Cells["Quantity"].Value.ToString()));
                billsitem.Remove(b);
                ServiceSale.Sale s = new ServiceSale.Sale();
                s = saledata.FirstOrDefault(m => m.Stock_ID == b.Stockid && m.Quantity == b.Quantity);
                saledata.Remove(s);
                load_sale();
            }
        }
        private void addtobill_Click(object sender, EventArgs e)
        {
            ServiceStock.StockData s = new ServiceStock.StockData();
            s = sdata.FirstOrDefault(m => m.Id == stockid[brproductlist.SelectedIndex]);
            ServiceSale.Sale row = new ServiceSale.Sale();
            row.Quantity = Int32.Parse(productquntity.Text);
            row.Stock_ID = stockid[brproductlist.SelectedIndex];
            row.Total    = row.Quantity * s.Price;
            saledata.Add(row);
            billgrid b = new billgrid();

            b.Name     = s.Name;
            b.Quantity = row.Quantity;
            b.Stockid  = row.Stock_ID;
            b.Price    = s.Price;
            b.Total    = (int)row.Total;
            billsitem.Add(b);

            load_sale();
        }