private void _addTarget() { if (!_targets.Any(t => t.MachineName == _selectedMachineName)) { var machine = _machine.Graph.Buzz.Song.Machines.SingleOrDefault(m => m.Name == _selectedMachineName); if (machine != null) { var targetModel = new Target(machine); ManagedMachine.AddTarget(targetModel); var targetView = new TargetVm(targetModel); targetView.PropertyChanged += Target_PropertyChanged; _targets.Add(targetView); PropertyChanged.Raise(this, "Targets"); } } }