Book Image

Mastering Ninject for Dependency Injection

By : Daniel Baharestani
Book Image

Mastering Ninject for Dependency Injection

By: Daniel Baharestani

Overview of this book

Dependency injection is an approach to creating loosely coupled applications. Maintainability, testability, and extensibility are just a few advantages of loose coupling. Ninject is a software library which automates almost everything that we need in order to implement a dependency injection pattern. Mastering Ninject for Dependency Injection will teach you everything you need to know in order to implement dependency injection using Ninject in a real-life project. Not only does it teach you about Ninject core framework features that are essential for implementing dependency injection, but it also explores the power of Ninject's most useful extensions and demonstrates how to apply them. Mastering Ninject for Dependency Injection starts by introducing you to dependency injection and what it's meant for with the help of sufficient examples. Eventually, you'll learn how to integrate Ninject into your practical project and how to use its basic features. Also, you will go through scenarios wherein advanced features of Ninject, such as Multi-binding, Contextual binding, providers, factories and so on, come into play. As you progress, Mastering Ninject for Dependency Injection will show you how to create a multilayer application that demonstrates the use of Ninject on different application types such as MVC, WPF, WCF, and so on. Finally, you will learn the benefits of using the powerful extensions of Ninject.
Table of Contents (12 chapters)

DI Containers

A DI container is an injector object that injects the dependencies into a dependent object. As we have seen in the previous example, we don't necessarily need a DI container in order to implement Dependency Injection. However, in more complex scenarios, a DI container can save a lot of time and effort by automating most of the tasks that we had to do manually. In real world applications, a single dependant class can have many dependencies, each of which have their own dependencies that forms a large graph of dependencies. A DI container should resolve the dependencies, and this is where the decision of selecting a concrete class for the given abstraction should be made. This decision is made by a mapping table, which is either based on a configuration file or is programmatically defined by the developer. We can see an example for both here:

<bind service="ILogger" to="ConsoleLogger" /> 

This one is an example of code-based configuration:


We can also define conditional rules instead of just mapping a service to a concrete type. We will discuss this feature in detail in Chapter 2, Getting Started with Ninject.

A container has the responsibility of dealing with the lifetime of the created objects. It should know how long an object should be kept alive, when to dispose of it, in what condition to return the existing instance, and in what condition to create a new one.


DI Containers are also known as IoC Containers.

There are other DI Container besides Ninject. You can find a list of them in Scott Hanselman's blog ( Unity, Castle Windsor, StructureMap, Spring.NET, and Autofac are a few of them:



Castle Windsor






Apache 2

Apache 2

Apache 2



Build on the "kernel" of ObjectBuilder.

Well documented and used by many.

Written by Jeremy D. Miller.

Written by Mark Pollack.

Written by Nicholas Blumhardt and Rinat Abdullin.