/// GET: /Billing/CreateInvoice /// <summary> /// Creates invoice in pdf by ID. /// </summary> /// <param name="invoiceId">Invoice ID.</param> /// <returns>PDF Invoice.</returns> public async Task <IActionResult> DownloadInvoice(long invoiceId) { var invoice = await _billingService.GetPdfInvoiceAsync(invoiceId); if (invoice == null) { return(BadRequest()); } return(File(invoice, "application/pdf", $"Invoice-{invoiceId}.pdf")); }