Imar, your book is very good for beginners.
Here below my suggestions to improve it even more.
I would remove the following sections in all the chapters:
- What you will learn in this chapter
- What you learned in this chapter
The core of the chapters are supposed to be read - actually studied. I think the above mentioned sections do not add anything. I find them a waste of space and time.
I would also replace the end-of-chapter exercises - which typically require a verbose answer - with a real programming exercise on the topic of the chapter. The solution to the exercise could be found on the site.
Appendix A could then be removed and a further chapter added to the book.
Furthermore, I think that the gap between your book and the "Professional ASP.NET" book by Wrox is not negligible.
I hope you will put your teaching skills at work and write a great intermediary book to fill the gap.