Dependency injection

When developing applications with Xperience, you may need to use service classes provided by the API. For example, services for managing users, handling digital marketing activities, and more.

To use a service, you first need to create a service instance. We recommend instantiating Xperience services via dependency injection.

Dependency injection design pattern

Dependency injection is a design pattern that is common to many programming languages and environments. Instead of instantiating a service instance inside a class constructor, you can pass the service instance into the constructor as a parameter. This way classes (e.g. controllers) do not need to obtain and configure the instance of a class they depend on.

The following code snippet shows a general example of the dependency injection design approach. Notice that the controller constructor accepts an instance of a service created by the dependency injection provider, without the need to instantiate explicitly.

public class AccountController : Controller
{
    private readonly IMembershipActivityLogger mMembershipActivityLogger;

    public AccountController(IMembershipActivityLogger membershipActivityLogger)
    {
        mMembershipActivityLogger = membershipActivityLogger;
    }

    ...

}

Developing applications with the dependency injection pattern in mind provides the following benefits:

• Less maintenance – changing object implementation is easier without strong coupling.
• Easier testing – application logic can be tested in isolation from its dependent objects.
• Loose coupling – classes are not directly dependent on one another.

Dependency injection providers

ASP.NET Core Web applications come with a dependency injection provider developed by Microsoft. The provider is designed to serve the needs of the framework and most consumer applications. However, it can also be replaced with any third-party service container that conforms with the current system requirements.

Xperience adds all of its services into the application’s IServiceCollection during the IServiceCollection.AddKentico() call (see Configure new projects). This approach is completely independent of the service provider used by the application.

For example, to substitute the default Microsoft service container with Autofac:

1. Add the Autofac.Extensions.DependencyInjection NuGet package to your project.

2. Call IHostBuilder.UseServiceProviderFactory(new AutofacServiceProviderFactory()) when building the web application.

   Program.cs

   Copy

   
   
    var builder = WebApplication.CreateBuilder(args);
   
    builder.Host.UseServiceProviderFactory(new AutofacServiceProviderFactory());
   
    // Register services directly with Autofac here
    builder.Host.ConfigureContainer<ContainerBuilder>(builder => builder.RegisterModule(new MyApplicationModule()));
   
    var app = builder.Build();
   
    

The application now uses Autofac for dependency resolution.