public void AutoGeneratePurchaseId() { decimal AlreadyExistData = _PurchaseRepository.AlreadyExistData(); int code = 1; if (AlreadyExistData >= 1) { var GetLastCode = _PurchaseRepository.GetLastPurchaseId(); if (GetLastCode != null) { code = Convert.ToInt32(GetLastCode.PurchaseId); code++; } txtPurchaseId.Text = code.ToString("000"); } else { txtPurchaseId.Text = "1001"; } }