C#

 public class A
{
    public static event EventHandler<YourEventArgs> GlobalEvent;
    
    public A()
    {
        // Attach a handler to the event
        A.GlobalEvent += new EventHandler<YourEventArgs>(delegate void (YourEventArgs e)
        {
            // Do what you want to here when the single event is fired to trigger all events.
        });
    }
}

class A {
    // A has an event to notify B instances with
    public event EventHandler OnA;
 
    public void Start() {
        B b1 = new B(1);
        // hook B event to my method
        b1.OnB += new EventHandler(CatchOnB);
        // hook B method to my event
        OnA += new EventHandler(b1.CatchOnA);
 
        B b2 = new B(2);
        b2.OnB += new EventHandler(CatchOnB);
        OnA += new EventHandler(b2.CatchOnA);
 
        b1.DoStuff();
        b2.DoStuff();
        if (OnA != null) {
            OnA(this, EventArgs.Empty);
        }
    }
 
    private void CatchOnB(object sender, EventArgs e) {
        Console.WriteLine("B{0} called me", ((B)sender).Id);
    }
}
 
class B {
    public event EventHandler OnB;

    public int Id;
 
    public B(int id) {
        this.Id = id;
    }
 
    public void CatchOnA(object sender, EventArgs e) {
        Console.WriteLine("A called B{0}", Id);
    }
 
    public void DoStuff() {
        if (OnB != null) {
            OnB(this, EventArgs.Empty);
        }
    }
}

cpotting wrote:

so that B3 does not have to know about object A?

cpotting wrote:

Can I call

Wassim Mansour wrote:

Is there a way to do this during the setup process?

Wassim Mansour wrote:

I had no clue on how to do this.