public ActionResult UpdateInvoice(Invoice invoice)
        {
            using (RMTechAdminDb db = new RMTechAdminDb())
            {
                foreach (InvoiceLine l in invoice.Lines)
                {
                    if (l.Id == 0)
                    {
                        db.InvoiceLines.Add(l);
                        invoice.InvoiceDate = DateTime.Now;
                        db.SaveChanges();
                    }
                    else
                    {
                        db.Entry(l).State = System.Data.Entity.EntityState.Modified;
                    }
                }


                db.Entry(invoice).State = System.Data.Entity.EntityState.Modified;

                db.SaveChanges();
                return(Content(Newtonsoft.Json.JsonConvert.SerializeObject(invoice)));
            }
        }
        public ActionResult SaveCustomer(Customer customer)
        {
            using (RMTechAdminDb db = new RMTechAdminDb())
            {
                if (customer.Id == 0)
                {
                    db.Customers.Add(customer);
                }
                else
                {
                    db.Entry(customer).State = System.Data.Entity.EntityState.Modified;
                }

                db.SaveChanges();
                return(Json("OK"));
            }
        }