public ActionResult UpdatePartial(InvoiceDetailModel model) { if (ModelState.IsValid) { try { if (model.ItemId == null && model.InvoiceSourceId == null) { ViewData["EditError"] = "Either Invoice Source or Item is required."; } else if (model.ItemId != null && model.InvoiceSourceId != null) { ViewData["EditError"] = "Only Invoice Source or Item can be entered at a time."; } else { InvoiceHelper.UpdateInvoiceDetail(model); } } catch (Exception e) { ViewData["EditError"] = e.Message; } } else { ViewData["EditError"] = "Please, correct all errors."; } return(PartialView("_Detail", InvoiceHelper.GetInvoiceDetail())); }