//remove an observer from the ObserverList
public void Unregister(Class_StockMarketDisplay observer)
{
this.ObserverList.Remove(observer);
}
//add an observer to the ObserverList and call update to make sure everything is upto date
public void Register(Class_StockMarketDisplay observer)
{
this.ObserverList.Add(observer);
observer.Update(this);
}
