All of these design patterns satisfy the S.O.L.I.D object-oriented design principles. Going through this chapter not only helped you revise your GoF patterns and fundamental S.O.L.I.D principles, but it will also help you keep in mind when you are designing your new classes to solve certain problems and hence increase the quality of your software.

We also covered some fundamentals of Inversion of Control via dependency injection and also went though some examples of DI using .NET Core. You would have also noticed that with the advent of DI, a lot of GoF patterns are automatically taken care of by the DI pattern. For example, almost all of the creational patterns can be replaced by the DI, while for many others, DI can complement them by taking care of part of their responsibility with regards to their implementation.

I hope you enjoyed this chapter as much as I did. This chapter provides the solid and essential basis for all of the design and code-heavy chapters in the remainder of this book.