Get a logging framework, e.g. Log4Net (
http://logging.apache.org/log4net/[
^]).
Add logging statements to all those functions manually, or add them using Aspect Oriented Programming methods (some Dependency Injection / Inversion of Control containers like Unity (
http://unity.codeplex.com/[
^]) offer "interception" which allows for adding extra functionality when a function / property is called).