Lutz Roeder’s .Net Reflector has been discussed on many blogs before, but I want to give it an additional plug. I recently had to emulate some C# serial-port code in our C++ app. The .Net SerialPort class is great, easy-to-use, and works well. Unfortunately, we’re using a C++ serial port library that does not support all the possible features. Fortunately, we have the source code and can easily extend it. Unfortunately, I’m not too familiar with serial port programming, and the .Net functionality does not all obviously map to the Win32 API in every respect.
Enter Reflector. It was trivial to poke into the .Net assemblies and see what the SerialPort class was doing under the covers and then use the correct Win32 functionality in our app.
There are also a ton of plugins available.