private void buttonShowInvoices_Click(object sender, EventArgs e)
        {
            Client client;

            client = ClientVM.DisplayClient;

            PrintInvoiceReportDialog printInvoiceReportDialog = new PrintInvoiceReportDialog();

            printInvoiceReportDialog.ClientVM = this.ClientVM;

            // Use InvoiceLookupApi to find and return invoice report based on client code.
            ClientVM.Invoices = InvoiceLookupApiClient.GetInvoicesByClient(client.ClientCode);
            printInvoiceReportDialog.ShowDialog();
        }
        // Print the invoice report for the selected client from the invoice database.
        private void buttonReport_Click(object sender, EventArgs e)
        {
            Client client;
            int    index = dataGridViewClients.CurrentRow.Index;

            client = (Client)clientVM.ClientsSource[index];

            PrintInvoiceReportDialog printInvoiceReportDialog = new PrintInvoiceReportDialog();

            printInvoiceReportDialog.ClientVM = this.clientVM;

            // Use InvoiceLookupApi to find and return invoice report based on client code.
            clientVM.Invoices = InvoiceLookupApiClient.GetInvoicesByClient(client.ClientCode);

            printInvoiceReportDialog.ShowDialog();
        }