1. Dependency Injection (DI) Or stop cooking spaghetti (code)

2. 1 “Dependency Injection is a key element of agile architecture” Ward Cunningham

3. Dependency Injection (DI) is not a pattern, but rather a set of tools 2

4. DIisone of the ways to applyInversion of Control (IoC) principle 3

5. Literally – let go off control and let someone feed you 4

6. Example Task Obviously its time to go to code . Check out NoDI project. 5

7. Specifications are singing rigoletto 6

8. Specs tend to change 7

9. Highly coupled code is a step to spaghetti code 8 Can’t intercept and change code; Can’t unit-test in isolation; Conceptual problems in modules design; Logic is spread across many parts.

10. Divide et impera 9 DI’s base is Interface Oriented Programming. Write your code against abstractions rather then concrete implementations.

11. Single Responsibility Principle (SRP) 10 By applying DI to class we let it “concentrate” on task it was designed for.

13. Reuse;

14. Build in parallel;

15. Easier to maintain;

16. Easier to unit-test.Go on and check this stuff applied in PoorMansDI project. 11

17. DI patterns. 12

18. Composition Root 13

19. Constructor injection 14

20. Property (setter) injection 15

21. Method injection 16

22. Ambient context 17

23. Which one to choose? 18

24. 3D of DI 19

25. 1. Composition 20

27. Singleton;

28. Per thread;

29. Per web request;

30. Per web session;

33. StructureMaphttp://structuremap.github.com/structuremap/index.html

34. Spring.Nethttp://www.springframework.net/

35. PikoContainerhttp://www.picocontainer.org/

36. Ninjecthttp://ninject.org/

37. Unity http://unity.codeplex.com/

38. PocoCapsule/C++ http://www.pocomatic.com

40. Pros? 25 Simplified component architecture; Easier to maintain; Replace; Reuse; Build in parallel; Easier to unit-test.

41. Cons? 26 Have to learn something new? Lower performance?(it depends) It might be hard to fix lifetime errors.

42. Should I use it? 27 Do you know OOP and design patterns? Do you write unit-tests? Do you use statically typed languages? First learn it. Don’t force a team that doesn’t see DI pros to use it.

43. Thank you! 28

44. Materials 30 M. Seemann. Dependency Injection in .Net - Manning Publications Co., 2010. R. Osherove. The art of Unit Testing - Manning Publications Co., 2009, ISBN: 978-933988-27-6. J. Miller. Cohesion And Coupling – MSDN Magazine, Oct. 2008. http://msdn.microsoft.com/en-us/magazine/cc947917.aspx F. Maulo. GuyWire. http://fabiomaulo.blogspot.com/2009/11/guywire.html K. Kozmic. How I use Inversion of Control containers. http://kozmic.pl/archive/2010/06/20/how-i-use-inversion-of-control-containers.aspx