public bool isExitReferenceInvoice(string refenceInvoice) { using (var db = new KoontabiDBEntities()) { var _referenceInvoice = db.SpValidateIfExitRefenceInvoice(refenceInvoice).FirstOrDefault(); return(_referenceInvoice != null? _referenceInvoice.ReferenceInvoice == 1:false); } }