public static ToTripRequiers GetInstance(Employee employee)
 {
     if (State == null)
     {
         State = new ToTripRequiers(employee);
     }
     if (State.employee.Id != employee.Id)
     {
         State = new ToTripRequiers(employee);
     }
     return(State);
 }
 private void ShowRequiersToTrip_Click(object sender, RoutedEventArgs e)
 {
     WorkingArea.Content = ToTripRequiers.GetInstance(employee);
 }