private void NewBillButton_Click(object sender, EventArgs e)
{
BillModel bill = new BillModel()
{
CustomerId = (CustomerComboBox.SelectedIndex == 0 ? null : (int?)CustomerComboBox.SelectedIndex),
EmployeeId = (EmployeeComboBox.SelectedIndex == 0 ? null : (int?)EmployeeComboBox.SelectedIndex),
CreatingDay = DateTime.Today.Date
};
bill.Id = LazyWorker <BillModel> .Insert(bill);
SetCurrentBill(LessLazyWorker.BillModelToBillDisplay(bill));
}
