public string jsonTransaction(string accountNumber, int inMonth, int inYear, bool isTransferred) { if (!Validate.validateAccountNmbr(accountNumber) || !Validate.validateMonthYear(inMonth, inYear)) { return(new JavaScriptSerializer().Serialize("error")); } List <TransactionPresentation> a = tranBLL.listTransactions(accountNumber, inMonth, inYear, isTransferred); return(new JavaScriptSerializer().Serialize(a)); }