The previous chapter continued the building of the FlixOne inventory management application by incorporating additional patterns. More of the Gang of Four patterns were used, including the Singleton and Factory patterns. The Singleton pattern was used to illustrate the Repository pattern that was used to maintain the FlixOne collection of books. The Factory pattern was used to further explore the dependency injection (DI). The .Net Core framework was used to complete the initial inventory management console application, in order to facilitate an inversion of control (IoC) container.

This chapter will continue building upon the inventory management console application, while also exploring features of .Net Core. The Singleton pattern, which was covered in the previous chapter, will be revisited and created, using the Singleton service lifetime built into the .Net Core framework. Using the framework's DI, the Configuration pattern will be shown, as well as constructor injection (CI) explained, using different examples.

The following topics will be covered in this chapter:

• .Net Core service lifetimes
• Implementation factory