The C# events implementation (articles vs reflector)

Answer 1

Yup: C# 4 has made some changes in this area, basically. It makes it thread-safe without locking. That's not the only change - it also changes how references to field-like events within the class are resolved: += and -= now go through the "add" and "remove" bits rather than working directly with the backing field.

Note that this change affects code compiled with the C# 4 compiler even against older frameworks; there are also changes to locking which only affect code compiled against .NET 4, as it uses a new method (Monitor.TryEnter(object, out bool)).