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Introduction

The recommended approach to employing a DI container in a software system is that the Composition Root of the application be the single place where the container is touched directly.

Unfortunately, many applications can’t create everything at once at a single point in time as application starts up or at the beginning of each incoming web/WCF request because not everything is known at that moment. These applications need a way to create new instances using the Kernel at a later time. Preferably this is done without introducing a reference to the container's types (or worse the container Kernel itself) away from the Composition Root.

Another unfortunately common antipattern which can become prevalent in the face of these types of constraints is use of the Service Locator antipattern.

This is where factories come into play. Instead of injecting the Kernel into types that need to create new instances we instead inject an instance of an Abstract Factory. This factory is responsible for creating the new instances (internally, indirectly using the Kernel to realize the goal). There are two ways to implement such a factory: A factory interface and as a Func or Lazy. Both ways are covered by this extension.

Binaries

• Latest build: http://teamcity.codebetter.com/viewLog.html?buildTypeId=bt293&buildId=lastSuccessful&tab=artifact

Documentation:

• Factory Interface
• Factory Interface - Named Bindings
• Factory Interface - custom instance provider
• Func
• Lazy