void personAdded(PersonManager personManager, PairablePerson pairablePerson) { this.Dispatcher.Invoke(new Action(delegate() { if (!PersonControlDictionary.ContainsKey(pairablePerson)) { PersonControlDictionary[pairablePerson] = new PersonControl(pairablePerson); canvas.Children.Add(PersonControlDictionary[pairablePerson]); } })); }