Implement Dependency Injection in Web API With Simple Injector

First, we have to know what dependency injection is. DI is a design pattern and with the help of this, we will develop a loosely coupled code.

This is a great idea but we will reduce tight coupling between the software components.

The main idea of DI is to develop a project with the code maintainable.

1. Constructor injection
2. Property injection
3. Method injection

In this article, we will develop DI with the help of Constructor injection.

Now start coding

Step 1

Open Visual Studio => New Project => Web => Visual Studio 2012 => ASP.Net MVC 4 Web Application and give a nice name to your project and click OK.

Step 2

Select empty template and click OK and your solution will be ready.



Step 3

I’m not going to make this solution too heavy for this. I made two folders in this solution and gave name BusinessLayer and DataAccessLayer.



In the folder BusinessLayer, make a class, name it as SchoolBusinessLayer.cs and an interface ISchoolBusinessLayer.cs.

Similarly, in DataAccessLayer, make a class, name it as SchoolDataAccessLayer.cs and an interface ISchoolDataAccesslayer.cs.

Step 4

Basically, DataAccesslayer is used to communicate with the database, but in this article, I’m not going to use any kind of database communication.

From DataAccess Layer, I am just going to return an object school with the data. Our goal is to develop dependency injection.

In the model, I made a class file School.cs and declared some property.



Step 5