public TransactionViewModel()
{
mainAtt = MainAtt.getInstance();
voucherVm = new VoucherViewModel();
dtServiceVM = new DetailServiceViewModel();
stockVM = new StockViewModel();
initDB();
}
public TransactionViewModel(string htID)
{
mainAtt = MainAtt.getInstance();
Ht = mainAtt.Mydb.HeaderTransactions.Where(a => a.HeaderID.Equals(htID)).FirstOrDefault();
voucherVm = new VoucherViewModel();
dtServiceVM = new DetailServiceViewModel();
stockVM = new StockViewModel();
initDB();
UpdateTotalPrice();
}