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Installation

To install, run dotnet add package SharpServiceCollection or from Nuget

Introduction

SharpServiceCollection is a lightweight C# library that wraps the IServiceCollection interface to streamline dependency injection through attribute-based assembly scanning.

Usage

• SharpServiceCollection scans an assembly to automatically register services in the IServiceCollection container.

• Use one of the extension methods of IServiceCollection to perform assembly scanning.

  • AddServicesFromCurrentAssembly()
  • AddServicesFromAssembly(Assembly assembly)
  • AddServicesFromAssemblyContaining<T>()
  • AddServicesFromAssemblyContaining(Type type)

Notes:

• SharpServiceCollection will perform lexicographical sort on the class name to register dependency when duplicates occur. For example, Foo Bar Baz will be sorted as Bar Baz Foo, If three of them are resolved by IDemoInterface, Non Try* based attributes will register the last one, which is Foo, Try* based attributes will register the first one, which is Bar
• InstanceLifetime is an Enum with the values Singleton Scoped Transient

Unified Attribute Approach

The InjectableDependencyAttribute provides a unified approach to dependency registration with flexible resolution strategies:

Non-Generic Version

[InjectableDependency(InstanceLifetime lifetime, ResolveBy resolveBy)]
[InjectableDependency(InstanceLifetime lifetime, ResolveBy resolveBy, string key)]

ResolveBy Enum:

• Self - Resolves the class by itself
• ImplementedInterface - Resolves by all implemented interfaces
• MatchingInterface - Resolves by interface with matching name (e.g., MyService → IMyService)
• SelfAndReplace - Same as Self but uses Add* methods (replaces existing)
• ImplementedInterfaceAndReplace - Same as ImplementedInterface but uses Add* methods (replaces existing)
• MatchingInterfaceAndReplace - Same as MatchingInterface but uses Add* methods (replaces existing)

Generic Version

[InjectableDependency<T>(InstanceLifetime lifetime)]
[InjectableDependency<T>(InstanceLifetime lifetime, bool replace)]
[InjectableDependency<T>(InstanceLifetime lifetime, string key)]
[InjectableDependency<T>(InstanceLifetime lifetime, bool replace, string key)]

Parameters:

• replace: false uses TryAdd* methods, true uses Add* methods
• key: For keyed services registration

Example with Unified Attribute Approach

public interface IUserService
{
    string GetUserInfo(int id);
}

using SharpServiceCollection.Attributes;
using SharpServiceCollection.Enums;

// Non-generic version
[InjectableDependency(InstanceLifetime.Scoped, ResolveBy.ImplementedInterface)]
public class UserService : IUserService
{
    public string GetUserInfo(int id) => $"User {id} information";
}

// Generic version
[InjectableDependency<IUserService>(InstanceLifetime.Singleton)]
public class CachedUserService : IUserService
{
    public string GetUserInfo(int id) => $"Cached User {id} information";
}

Granular Attribute Approach

• IServiceCollection comes with Add* and TryAdd* methods. SharpServiceCollection offers the same functionality.
• In general, it is better to use Try* based attributes.

using SharpServiceCollection.Attributes;
using SharpServiceCollection.Enums;

// The class will be resolvable by the interface specified in the generic argument
[TryResolveBy<IScopedDemoService>(InstanceLifetime.Scoped)]
[ResolveBy<IScopedDemoService>(InstanceLifetime.Scoped)]
public class ScopedDemoType : IScopedDemoService, IKeyedScopedDemoService
{
}

// The class will be resolvable by the interface specified in the generic argument and the key
[KeyedTryResolveBy<IKeyedScopedDemoService>(InstanceLifetime.Scoped, "keyed")]
[KeyedResolveBy<IKeyedScopedDemoService>(InstanceLifetime.Scoped, "keyed")]
public class ScopedDemoType : IScopedDemoService, IKeyedScopedDemoService
{
}

// The class will be resolvable by itself
[TryResolveBySelf(InstanceLifetime.Scoped)]
[ResolveBySelf(InstanceLifetime.Scoped)]
public class ScopedDependency : IScopedDependency
{
}

// This will work by convention
// The class must have to implement an interface that has the same name of the class prefixed with I
[TryResolveByMatchingInterface(InstanceLifetime.Scoped)]
[ResolveByMatchingInterface(InstanceLifetime.Scoped)]
public class ScopedDependency : IScopedDependency
{
}

// The class will be resolvable by any of the implementeed interface
[TryResolveByImplementedInterface(InstanceLifetime.Scoped)]
[ResolveByImplementedInterface(InstanceLifetime.Scoped)]
public class FooBarBaz : IFoo, IBar, IBaz
{
}

Example With Granular Attribute Approach

public interface IDemoService
{
    string Greet();
}

using SharpServiceCollection.Attributes;
using SharpServiceCollection.Enums;

[TryResolveByImplementedInterface(InstanceLifetime.Scoped)]
public class DemoService : IDemoService
{
    public string Greet()
    {
        return "Hello World!";
    }
}

using SharpServiceCollection.Extensions;

var builder = WebApplication.CreateBuilder(args);

// Current assembly will be scanned by Assembly.GetCallingAssembly()
builder.Services.AddServicesFromCurrentAssembly();

var app = builder.Build();

app.MapGet("/", (IDemoService demoService) => demoService.Greet());

app.Run();