Tags

Tags allow filtering service registrations at runtime by passing tag parameters to the extension method.

Basic Tags

[IocRegisterDefaults<IHandler>(ServiceLifetime.Transient, Tags = ["Mediator"])]
public interface IHandler;

[IocRegister]
internal class MyHandler : IHandler;

This generates a single method with a params IEnumerable<string> tags parameter:

Generated Code

public static IServiceCollection AddMyProject(this IServiceCollection services, params IEnumerable<string> tags)
{
    // Services with tags: only register when matching tags are passed
    if (tags.Contains("Mediator"))
    {
        services.AddTransient<global::MyNamespace.MyHandler, global::MyNamespace.MyHandler>();
        services.AddTransient<global::MyNamespace.IHandler>((global::System.IServiceProvider sp) => sp.GetRequiredService<global::MyNamespace.MyHandler>());
    }

    return services;
}

Behavior (Mutually Exclusive Model)

• Services without tags: Only registered when no tags are passed
• Services with tags: Only registered when matching tags are passed

Tags act as mutually exclusive group selectors. This enables scenarios like environment-specific configurations where you switch between different service implementations rather than adding to them.

Multiple Tags

[IocRegister<IService>(Tags = ["Feature1", "Feature2"])]
internal class MyService : IService;

The service is registered when any of the specified tags match:

Generated Code

if (tags.Contains("Feature1") || tags.Contains("Feature2"))
{
    // Register MyService
}

Mixed Services

[IocRegister<IService>(Tags = ["Feature1"])]
internal class FeatureService : IService;

[IocRegister<IService>]
internal class DefaultService : IService;

This generates:

Generated Code

public static IServiceCollection AddMyProject(this IServiceCollection services, params IEnumerable<string> tags)
{
    // Services without tags - only register when no tags passed
    if (!tags.Any())
    {
        services.AddTransient<global::MyNamespace.DefaultService, global::MyNamespace.DefaultService>();
        services.AddTransient<global::MyNamespace.IService>((global::System.IServiceProvider sp) => sp.GetRequiredService<global::MyNamespace.DefaultService>());
    }

    // Services with tags - only register when tags match
    if (tags.Contains("Feature1"))
    {
        services.AddTransient<global::MyNamespace.FeatureService, global::MyNamespace.FeatureService>();
        services.AddTransient<global::MyNamespace.IService>((global::System.IServiceProvider sp) => sp.GetRequiredService<global::MyNamespace.FeatureService>());
    }

    return services;
}

Using Tags

// Register only services without tags (default configuration)
services.AddMyProject();

// Register only services matching "Mediator" tag (NOT services without tags)
services.AddMyProject(["Mediator"]);

// Register only services matching "Feature1" or "Feature2" tags (NOT services without tags)
services.AddMyProject(["Feature1", "Feature2"]);

// Using an array of tags
string[] myTags = ["Mediator", "Feature1"];
services.AddMyProject(myTags);

Tags with Defaults

Apply tags to all implementations via IocRegisterDefaults:

[IocRegisterDefaults<IMediator>(
    ServiceLifetime.Singleton,
    Tags = ["Mediator"])]  // All IMediator implementations only register when "Mediator" tag is passed
public interface IMediator;

[IocRegister]
internal class Mediator : IMediator;  // Only registered with AddMyProject(["Mediator"])

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