abp-dependency-injection

name	abp-dependency-injection
description	ABP Framework v10.x (10.4/10.5) dependency injection: ITransientDependency/IScopedDependency/ISingletonDependency, [Dependency], [ExposeServices], LazyServiceProvider, property injection, Autofac. Use when you need service registration, DI, or automatic registration in ABP.

ABP Dependency Injection Skill

Trigger

Dependency injection, DI, ITransientDependency, ISingletonDependency, IScopedDependency, [Dependency], [ExposeServices], auto registration, Autofac.

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Quick Reference

Conventional Registration (auto)

public class TaxCalculator : ITransientDependency { }  // Transient
public class CacheService : ISingletonDependency { }   // Singleton
public class RequestTracker : IScopedDependency { }    // Scoped

[Dependency] Attribute

[Dependency(ServiceLifetime.Transient, ReplaceServices = true)]
public class TaxCalculator { }

[Dependency(ServiceLifetime.Singleton, TryRegister = true)]
public class MyCacheService { }

Properties: Lifetime, TryRegister, ReplaceServices Higher priority than dependency interfaces.

[ExposeServices] Attribute

[ExposeServices(typeof(ITaxCalculator))]
public class TaxCalculator : ICalculator, ITaxCalculator, ITransientDependency { }

Only ITaxCalculator injectable. Without attribute, all interfaces exposed.

Disable Auto Registration

public class BlogModule : AbpModule
{
    public BlogModule() { SkipAutoServiceRegistration = true; }
    public override void ConfigureServices(ServiceConfigurationContext context)
    {
        context.Services.AddAssemblyOf<BlogModule>();
    }
}

Autofac (required for dynamic proxying)

dotnet add package Volo.Abp.Autofac

[DependsOn(typeof(AbpAutofacModule))]
public class MyModule : AbpModule { }

Program.cs: builder.Host.UseAutofac();

Property Injection

public class MyService : ITransientDependency
{
    public IEmailSender EmailSender { get; set; } // Optional dependency
}

Override Framework Service

[Dependency(ReplaceServices = true)]
public class MyCustomEmailSender : IEmailSender, ITransientDependency { }

Best Practices

• ITransientDependency for most services
• Constructor injection preferred
• [Dependency(ReplaceServices=true)] to override framework services
• [ExposeServices] to limit exposed interfaces
• ISingletonDependency only for stateless/caches
• Don't use service locator pattern
• Autofac required for interceptors (UOW, validation, auth, audit)

Related

Framework · Modularity · DDD · Docs: https://abp.io/docs/latest/framework/fundamentals/dependency-injection