public ResultViewModel <IEnumerable <InvoiceItemViewModel> > GetAll()
        {
            ResultViewModel <IEnumerable <InvoiceItemViewModel> > result
                = new ResultViewModel <IEnumerable <InvoiceItemViewModel> >();

            try
            {
                result.Successed = true;
                result.Data      = InvoiceItemService.GetAll();;
            }
            catch (Exception ex)
            {
                result.Successed = false;
                result.Message   = "Semething Went Wrong";
            }
            return(result);
        }