@Keith
The difficulty with a google search ( even a search here ) is dissecting the 'good' information from the rest. There has been a lot of guesses made publically about .net code and the AutoCAD API in the last 10 years
.. unfortunately not all of them are correct.
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AutoCAD and .NET API's are both complex topics, more so for beginners.
Combining the 2 topics for people with limited experience is most certainly a challenge.
Using a "recipe" format, putting suitable samples into one place is a proven teaching method, allowing for individual progression.