public ActionResult Input(string id = "")
 {
     try
     {
         if (string.IsNullOrEmpty(id))
         {
             ViewBag.Title = " Create new Customer";
             Customer newCustomer = new Customer()
             {
                 CustomerID = ""
             };
             return(View(newCustomer));
         }
         else
         {
             ViewBag.Title = "Edit a Customer";
             Customer editCustomer = CataLogBLL.GetCustomer(id);
             return(View(editCustomer));
         }
     }catch (Exception ex)
     {
         return(Content(ex.Message + "" + ex.StackTrace));
     }
 }
        public ActionResult Input(Customer model)
        {
            try
            {
                if (string.IsNullOrEmpty(model.CustomerID))
                {
                    ModelState.AddModelError("CustomerID", "CustomerID expected");
                }
                if (string.IsNullOrEmpty(model.CompanyName))
                {
                    ModelState.AddModelError("CompanyName", "CompanyName expected");
                }
                if (string.IsNullOrEmpty(model.ContactName))
                {
                    ModelState.AddModelError("ContactName", "ContactName expected");
                }
                if (string.IsNullOrEmpty(model.ContactTitle))
                {
                    ModelState.AddModelError("ContactTitle", "ContactTitle expected");
                }
                if (string.IsNullOrEmpty(model.Address))
                {
                    model.Address = "";
                }
                if (string.IsNullOrEmpty(model.City))
                {
                    model.City = "";
                }
                if (string.IsNullOrEmpty(model.Country))
                {
                    model.Country = "";
                }
                if (string.IsNullOrEmpty(model.Fax))
                {
                    model.Fax = "";
                }
                if (string.IsNullOrEmpty(model.Phone))
                {
                    model.Phone = "";
                }
                if (!ModelState.IsValid)
                {
                    ViewBag.Title = model.CustomerID == "" ? "Create new Customer" : "Edit a Customer";
                    return(View(model));
                }

                Customer getCustomer = CataLogBLL.GetCustomer(model.CustomerID);
                if (getCustomer == null)
                {
                    // model.CustomerID = method;
                    CataLogBLL.AddCustomer(model);
                }
                else
                {
                    CataLogBLL.UpdateCustomer(model);
                }
                return(RedirectToAction("Index"));
            }
            catch (Exception ex)
            {
                return(Content(ex.Message + "" + ex.StackTrace));
                //ModelState.AddModelError("Loi", ex.StackTrace);
                //return View(model);
            }
        }