What is the preferred way to bubble events?

Question

I have three objects ObjectA has an ObjectB, ObjectB has an ObjectC. When ObjectC fires an event I need ObjectA to know about it, so this is what I\'ve done...

Answer 1

That's the way I do it. however I would recommend change your firing mechanism to this to make it thread safe

protected void OnEventFired()
{
    var tmpEvent = EventFired;
    if(tmpEvent != null)
    {
        tmpEvent();
    }
}

This keeps it from failing if EventFired becomes null between the null check and the firing.

Also it is somewhat of a standard to follow the EventHandler pattern for your event delegates.

protected virtual void OnEventFired(EventArgs e)
{
    var tmpEvent = EventFired;
    if(tmpEvent != null)
    {
        tmpEvent(this, EventArgs.e);
    }
}

---

I was wrong about the threadsafe pattern, here is the full threadsafe event pattern

/// 

/// Delegate backing the SomeEvent event.
/// 
SomeEventHandler someEvent;

/// 

/// Lock for SomeEvent delegate access.
/// 
readonly object someEventLock = new object();

/// 

/// Description for the event
/// 
public event SomeEventHandler SomeEvent
{
    add
    {
        lock (someEventLock)
        {
            someEvent += value;
        }
    }
    remove
    {
        lock (someEventLock)
        {
            someEvent -= value;
        }
    }
}

/// 

/// Raises the SomeEvent event
/// 
protected virtual OnSomeEvent(EventArgs e)
{
    SomeEventHandler handler;
    lock (someEventLock)
    {
        handler = someEvent;
    }
    if (handler != null)
    {
        handler (this, e);
    }
}