private void bSellItemAdd_Click(object sender, EventArgs e)
 {
     QuantityForm form = new QuantityForm();
     if (form.ShowDialog(1, DbActionsEnum.Create) == System.Windows.Forms.DialogResult.OK)
     {
         SaleItem si = new SaleItem(form.ResultData, this.prodsSellTab.getSelectedProduct());
         this.saleCart.addSaleItem(si);
     }
 }
 private void bSaleItemEdit_Click(object sender, EventArgs e)
 {
     QuantityForm form = new QuantityForm();
     SaleItem pi = this.items[this.dgvSaleItems.SelectedRows[0].Index];
     if (form.ShowDialog(pi.Quantity, DbActionsEnum.Update) == System.Windows.Forms.DialogResult.OK)
     {
         pi.Quantity = form.ResultData;
         this.dgvSaleItems.Refresh();
     }
 }