Are C# delegates thread-safe?

Question

If you have a class instance with a delegate member variable and multiple threads invoke that delegate (assume it points to a long-running method), is there any contention i

Answer 1

Modifying an event is not thread-safe, but invoking a delegate is. Since a delegate is immutable, it is thread-safe. See remarks here MSDN Delegate class:

Borrowed from here: In CLR Via C# Richter points out a few subtle points about event invocation in multi-threaded classes:

A delegate chain is immutable; a new chain is created to replace the first. A delegate chain with zero subscribers is null. That means (if your event is public) it may transition from null to non-null and vice versa, at any time.