Observer Pattern

public class Subject
{
List<IObserver> _subjects = new List<IObserver>();
string _message = string.Empty;
public void Subscribe(IObserver Subject)
{
_subjects.Add(Subject);
}
private void NotifySubscriber()
{
_subjects.ForEach(subject => subject.UpdateState());
}
public string GetMessage()
{
return _message;
}
public void SetMessage(string Message)
{
_message = Message;
NotifySubscriber();
}
}
public interface IObserver
{
Subject subject { get; set; }
void UpdateState();
}
public class Subscriber1 : IObserver
{
public Subscriber1(Subject OSubject)
{
this.subject = OSubject;
this.subject.Subscribe(this);
}
public Subject subject { get; set; }
public void UpdateState()
{
Console.WriteLine("Subscriber 1 is notified with value: " + subject.GetMessage());
}
}
public class Subscriber2 : IObserver
{
public Subscriber2(Subject OSubject)
{
this.subject = OSubject;
this.subject.Subscribe(this);
}
public Subject subject { get; set; }
public void UpdateState()
{
Console.WriteLine("Subscriber 2 is notified with value: " + subject.GetMessage());
}
}
//Consume Observer pattern
Subject oSubject = new Subject();
Subscriber1 osub1 = new Subscriber1(oSubject);
Subscriber2 osub2 = new Subscriber2(oSubject);
Console.WriteLine("====This is a test message 1====");
oSubject.SetMessage("First message from Subject");
Console.WriteLine("====This is a test message 2====");
oSubject.SetMessage("Second message from Subject");
Console.ReadLine();