Avoid race condition ?. operator

Question

Does the ?. operator that can be used to invoke a delegate or event avoid race conditions?

Eg. avoid race-condition manually:

//The event-invoking method that derived classes can override.
        protected virtual void OnShapeChanged(ShapeEventArgs e)
        {
            // Make a temporary copy of the event to avoid possibility of
            // a race condition if the last subscriber unsubscribes
            // immediately after the null check and before the event is raised.
            EventHandler<ShapeEventArgs> handler = ShapeChanged;
            if (handler != null)
            {
                handler(this, e);
            }
        }

source: msdn

Manny

Yes. codeblog.jonskeet.uk/2015/01/30/… – Viewless

Answer 1

Yes

Another use for the null-condition member access is invoking delegates in a thread-safe way with much less code.

...

The new way is thread-safe because the compiler generates code to evaluate PropertyChanged one time only

MSDN Source

Galenical

thx btw the example from msdn also works without overriding the virtual method. Do you know why is that? – Manny

@GernotAtStackoverflow what virtual method are you referring to? – Galenical

protected virtual void OnShapeChanged(ShapeEventArgs e) – Manny

sry I got it... forget that – Manny