public bool ValidateInvoiceNo(string _invoiceNo, string _invId) { if (!string.IsNullOrEmpty(_invoiceNo)) { invObj = new InvoiceClass(); invObj.invoiceNo = _invoiceNo; invObj.invId = Convert.ToInt32(_invId); if (invObj.ValidateInvoiceNo()) { return(true); } else { return(false); } } else { return(false); } }