Asp net core di with simple injector sharing dbcontext

Introduction

ASP.NET is a popular language used for building web applications. One common challenge that developers face is managing dependencies and sharing resources across different components of an . In this article, we will explore how to use ASP.NET Core DI ( Injection) with Simple Injector to share a DbContext instance.

What is Dependency Injection?

Dependency Injection is a design pattern that allows the separation of concerns and promotes loose coupling between components. It enables the of reusable and testable code by providing dependencies to a class from an external source rather than creating them internally.

Using Simple Injector with ASP.NET Core DI

Simple Injector is a lightweight and extensible dependency injection framework for .NET. It provides a simple and intuitive API for registering and resolving dependencies. To use Simple Injector with ASP.NET Core DI, we need to install the SimpleInjector.Integration.AspNetCore NuGet package.


// Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft..Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using SimpleInjector;
using SimpleInjector.Lifestyles;

public class Startup
{
    private Container container = new Container();

    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers();

        // Register Simple Injector container as the default service provider
        services.AddSingleton(new SimpleInjectorControllerActivator(container));
        services.EnableSimpleInjectorCrossWiring(container);
        services.UseSimpleInjectorAspNetRequestScoping(container);

        // Register your dependencies here
        container.Register(Lifestyle.Scoped);
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        // Other configuration code

        // Use Simple Injector as the  lifetime scope
        app.UseSimpleInjector(container);

        // Other configuration code
    }
}

Sharing DbContext with Simple Injector

When using Simple Injector with ASP.NET Core DI, we can easily share a DbContext instance across multiple components. To achieve this, we need to register the DbContext as a scoped dependency in the container.


// MyController.cs

using Microsoft.AspNetCore.Mvc;
using System.Linq;

public class MyController : ControllerBase
{
    private readonly DbContext dbContext;

    public MyController(DbContext dbContext)
    {
        this.dbContext = dbContext;
    }

    public IActionResult Get()
    {
        // Use the  DbContext instance
        var data = dbContext.Set().ToList();

        return Ok(data);
    }
}

In the above example, we have a named MyController that depends on a DbContext instance. By injecting the DbContext into the controller's constructor, we can the shared instance within the controller's actions.

Conclusion

By using ASP.NET Core DI with Simple Injector, we can easily manage dependencies and share resources like DbContext instances across different components of an application. This promotes code reusability, testability, and maintainability. It is important to properly configure the container and register dependencies to ensure the lifetime scope and behavior of shared instances.

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