public MainWindow()
{
InitializeComponent();
// Set Sources
_tickets = TicketManager.GetTickets();
TicketListView.ItemsSource = _tickets;
_finances = FinanceManager.GetFinances();
FinancesListView.ItemsSource = _finances;
_businesses = CustomerManager.GetCustomers();
BussinessListView.ItemsSource = _businesses;
_techs = TechnicianManager.GetTechnicians();
TechListView.ItemsSource = _techs;
}