public bool SaveDetail() { string invoiceno; // 先检查发票号是否已存在 foreach (string id in _AddList) { invoiceno = _POInvoices.Find(o => o.id == id).invoiceno; if (proxy.CheckExistInvoice(invoiceno) || _POInvoices.Where(o => o.invoiceno == invoiceno).Count() > 1) { MessageBox.Show("该发票已登记存在,不能再次登记使用"); return(false); } } foreach (string id in _AddList) { proxy.AddPOInvoice(_POInvoices.Find(o => o.id == id)); } foreach (string id in _DelList) { proxy.DeletePOInvoice(id); } proxy.ResetPayStatus(this.PO.pono); return(true); }