private async void Button_Click(object sender, RoutedEventArgs e)
        {
            var invoiceAPI = UnicontaAPIManager.GetInvoiceAPI();
            var debtor     = this.GetSelectedCustomer();

            // QuickInvoice
            var debtorOrder = new DebtorOrder
            {
            };

            debtorOrder.SetMaster(debtor);

            var debtorOrderLines = new List <DebtorOrderLine>();
            var debtorOrderLine  = new DebtorOrderLine
            {
            };

            debtorOrderLine.SetMaster(debtorOrder);
            debtorOrderLines.Add(debtorOrderLine);

            //TODO: Use new API
            var invoiceErrorCode = await invoiceAPI.PostInvoice(debtorOrder, debtorOrderLines, DateTime.Now, 0, false, null, null, true, false);

            if (invoiceErrorCode.Err != ErrorCodes.Succes)
            {
                return;
            }
        }
        private async void AddOrderLine()
        {
            var invoiceAPI = UnicontaAPIManager.GetInvoiceAPI();
            var newOrder   = new DebtorOrder
            {
            };

            newOrder.SetMaster(this.selectedCustomer);

            var timeUsage = (DateTime.Now - this.startTime).TotalHours;

            if (timeUsage < 0.5)
            {
                timeUsage = 0.5;
            }

            var newOrderLines = new List <DebtorOrderLine>();
            var newOrderLine  = new DebtorOrderLine
            {
                _Text     = "Onsite",
                _Qty      = timeUsage,
                _Price    = 890,
                _Currency = Currencies.DKK,
            };

            newOrderLine.SetMaster(newOrder);
            newOrderLines.Add(newOrderLine);

            var invoiceresult = await invoiceAPI.PostInvoice(newOrder, newOrderLines, DateTime.Now, -1, false);

            if (invoiceresult.Err != ErrorCodes.Succes)
            {
            }
        }