避免竞争条件？操作员

Question

可用于调用委托或事件的 ?. 运算符是否避免了竞争条件？

例如。手动避免竞争条件：

//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);
            }
        }

来源：msdn

Answer 1

是

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

避免竞争条件？操作员

Avoid race condition ?. operator

c#

events

delegates

race-condition