Introducing an IoC Container to Legacy Code

Question

I\'m writing a new .NET library for internal use at my company that will use IoC through Dependency Injection. Naturally, this library will be much easier to use if we use

Answer 1

You can use a facade / proxy pattern to hide the DI Container from your legacy container. You are essentially hardwiring your legacy to a custom class that you implement which will know about the DI container. Now if you modify your DI you update your facades not your legacy code.

I've not done a lot of research into Common Service Locator but it's premise might be a good solution. You might want to tie your facade to the CSL, this will hide the DI concept completly from your legacy code.

Answer 2

As I understand your question, you want to invoke DI-enabled code from legacy code.

The best option is to keep the new library DI Friendly, but container-agnostic.

Doing this, you can provide a simple Facade the legacy code can use. No need for the legacy app to use any DI Container, and no need for the Common Service Locator.