public AdminManagement()
        {
            InitializeComponent();
            List <Room>     rooms     = roomViewModel.FindAll();
            List <Employee> employees = employeeViewModel.FindAll();

            RoomsGrid.ItemsSource  = rooms;
            RoomTypeCb.ItemsSource = typeRoomViewModel.FindAllActive();

            EmployeesGrid.ItemsSource = employees;
            RoleTypeCb.ItemsSource    = roleViewModel.FindAll();

            CustomersGrid.ItemsSource = customerViewModel.FindAll();

            TypeRoomsGrid.ItemsSource = typeRoomViewModel.FindAllActive();
        }