MPDemo is a program written by Wilfried Mestdagh that shows you how to use the most important API features using C#.
Using this application you can check out what you want to do and step with the debugger through it to see the code.
The code is written using separate classes in separate files as much as possible. Events are used at the places where a GUI update is needed.
You will get lifetime free upgrades of the source, even if the price will raise in future. Note that you must have Microsoft .NET version 2 installed to run the executable.