How do I know if this C# method is thread safe?

Question

I\'m working on creating a call back function for an ASP.NET cache item removal event.

The documentation says I should call a method on an object or calls I know wil

Answer 1

any access to an obect that can be used simultaneously by two threads is not threadsafe.

your example in Part 2 is clearly safe, as it uses only values passed in as arguments, but if you used an object scoped variable you might have to surround the access with appropriate lock statements