When building web applications with ASP.NET Core or ASP.NET Core MVC, developers often encounter situations where the same dependency injection (DI) code is repeatedly used across multiple controllers. This redundancy can lead to bloated code and violate the DRY (Don’t Repeat Yourself) principle, making the code harder to maintain and extend. Dependency injection is a powerful feature of ASP.NET Core, but without careful organization, it can result in unnecessary repetition in each controller that requires similar services.
To address this problem, one effective strategy is to create a custom base controller that encapsulates common DI logic. This allows you to centralize the dependency injection in one place, avoiding the need to repeat the same code in every controller. By extending the custom base controller, all derived controllers can inherit the necessary services, reducing redundancy and promoting cleaner, more maintainable code. In this article, we will explore how to implement such a base controller and eliminate unnecessary DI code repetition.
Before diving into the implementation, you should ensure that you have Visual Studio 2019 installed on your system, as the examples provided are designed to work within that IDE. If you don’t have Visual Studio 2019, you can download it from the official Microsoft website to get started. Once you have the environment set up, we can move on to creating an ASP.NET Core MVC project where we will implement dependency injection in a more streamlined way.
To create the project, open Visual Studio 2019 and follow these steps: launch the IDE, click on “Create new project,” and choose the “ASP.NET Core Web App (Model-View-Controller)” template. After selecting the template, specify the project name and location in the configuration window, and choose .NET 5.0 as the target framework. Make sure to leave the default authentication settings and disable options like Docker and Razor runtime compilation, which aren’t needed for this example. Once the project is created, you will be ready to implement the custom base controller and begin refactoring your DI code for better efficiency and readability.