// GET: 客戶資料
        public ViewResult Index(string sortOrder, string currentOrder, string searchString, string 客戶分類)
        {
            var customer = repo客戶.All();

            ViewBag.客戶分類SelectList = new SelectList(items: repo客戶.客戶分類GroupByList().ToList());

            if (!String.IsNullOrEmpty(searchString))
            {
                if (!String.IsNullOrEmpty(客戶分類))
                {
                    customer = repo客戶.CategoryQuery(客戶分類, searchString);
                }
                else
                {
                    customer = repo客戶.Search(searchString);
                }
                return(View(customer.ToList()));
            }
            else if (!String.IsNullOrEmpty(客戶分類))
            {
                customer = repo客戶.CategoryQuery(客戶分類, searchString);
                return(View(customer.ToList()));
            }
            else
            {
                sortOrder = String.IsNullOrEmpty(sortOrder) ? "客戶名稱" : sortOrder;

                switch (sortOrder)
                {
                case "客戶名稱":
                    if (currentOrder == "客戶名稱_desc")
                    {
                        customer             = customer.OrderByDescending(p => p.客戶名稱);
                        ViewBag.currentOrder = "客戶名稱";
                    }
                    else
                    {
                        customer             = customer.OrderBy(p => p.客戶名稱);
                        ViewBag.currentOrder = "客戶名稱_desc";
                    }
                    break;

                case "統一編號":
                    if (currentOrder == "統一編號_desc")
                    {
                        customer             = customer.OrderByDescending(p => p.統一編號);
                        ViewBag.currentOrder = "統一編號";
                    }
                    else
                    {
                        customer             = customer.OrderBy(p => p.統一編號);
                        ViewBag.currentOrder = "統一編號_desc";
                    }
                    break;

                case "電話":
                    if (currentOrder == "電話_desc")
                    {
                        customer             = customer.OrderByDescending(p => p.電話);
                        ViewBag.currentOrder = "電話";
                    }
                    else
                    {
                        customer             = customer.OrderBy(p => p.電話);
                        ViewBag.currentOrder = "電話_desc";
                    }
                    break;

                case "傳真":
                    if (currentOrder == "傳真_desc")
                    {
                        customer             = customer.OrderByDescending(p => p.傳真);
                        ViewBag.currentOrder = "傳真";
                    }
                    else
                    {
                        customer             = customer.OrderBy(p => p.傳真);
                        ViewBag.currentOrder = "傳真_desc";
                    }
                    break;

                case "地址":
                    if (currentOrder == "地址_desc")
                    {
                        customer             = customer.OrderByDescending(p => p.地址);
                        ViewBag.currentOrder = "地址";
                    }
                    else
                    {
                        customer             = customer.OrderBy(p => p.地址);
                        ViewBag.currentOrder = "地址_desc";
                    }
                    break;

                case "Email":
                    if (currentOrder == "Email_desc")
                    {
                        customer             = customer.OrderByDescending(p => p.Email);
                        ViewBag.currentOrder = "Email";
                    }
                    else
                    {
                        customer             = customer.OrderBy(p => p.Email);
                        ViewBag.currentOrder = "Email_desc";
                    }
                    break;

                default:
                    break;
                }
                return(View(customer.ToList()));
            }
        }