| patterns/observer/template/observer-only.cs - A templates of the Observer class. | Lecture 6 - slide 17 : 20 Program 2  | 
using System.Collections;
namespace Templates.Observer {
 public class Observer {                      
   private Subject mySubject;                 
                                              
   public Observer (Subject s){               
     mySubject = s;
   }   
   public void Update(){                      
      // ...                                  
      SubjectState state = mySubject.GetState();   
                                                   
      //   if (the state is interesting){
      //      react on state change
      //   }
   }
 }
}