private void InvoiceAddItemForm_Load(object sender, EventArgs e)
        {
            BLItem bl = new BLItem();

            list = bl.BLGetItem();
            foreach (ItemModel item in list)
            {
                comboBoxItem.Items.Add(item.itemName.ToString());
            }

            if (invoiceDetailId == 0)
            {
                btnSave.Text = "Salveaza";
            }
            else
            {
                btnSave.Text = "Modifica";
            }
        }