Top 10 ASP.NET Core Interview Questions and Answers

 

1. What is ASP.NET Core?

Answer: ASP.NET Core is a cross-platform, high-performance, open-source framework for building modern, cloud-based, and internet-connected applications. It is a redesign of ASP.NET with improved performance, modularity, and ease of deployment.

---------------------------------------------------------------- 

2. What are the key differences between ASP.NET Core and ASP.NET?

Answer:  below are the key differences,

Cross-Platform: ASP.NET Core supports Windows, macOS, and Linux, whereas traditional ASP.NET is primarily Windows-based.

Performance: ASP.NET Core offers improved performance and scalability.

Modularity: ASP.NET Core is more modular with a smaller footprint, thanks to its NuGet package-based architecture.

Hosting: ASP.NET Core can be self-hosted or hosted on IIS, unlike ASP.NET, which relies on IIS.

---------------------------------------------------------------- 

3. Describe the role of the Startup class in ASP.NET Core.

Answer: The Startup class in ASP.NET Core is used to configure services and the app's request pipeline. It typically contains two methods:

ConfigureServices: Used to register services with the dependency injection container.

Configure: Used to define the middleware components that process requests and responses.

---------------------------------------------------------------- 

4. Explain Dependency Injection in ASP.NET Core.

Answer: Dependency Injection (DI) is a design pattern used in ASP.NET Core to achieve Inversion of Control (IoC) between classes and their dependencies. ASP.NET Core has a built-in DI container that allows services to be registered and injected into constructors of classes where they are needed.

---------------------------------------------------------------- 

5. What is middleware in ASP.NET Core and how is it used?

Answer: Middleware in ASP.NET Core is software that is assembled into an app's request pipeline to handle requests and responses. Each piece of middleware can perform operations before and after the next component in the pipeline. Middleware components are added in the Configure method of the Startup class using methods like app.UseMiddleware<>().

---------------------------------------------------------------- 

6. How do you handle configuration in ASP.NET Core?

Answer: Configuration in ASP.NET Core is handled using the ConfigurationBuilder class, which supports a variety of configuration sources such as JSON files, environment variables, and command-line arguments. Configuration settings are typically accessed through the IConfiguration interface.

---------------------------------------------------------------- 

7. How do you handle authentication and authorization in ASP.NET Core?

Answer: Authentication and authorization in ASP.NET Core are handled using middleware and services configured in the Startup.ConfigureServices and Startup.Configure methods. Common authentication options include cookie-based, JWT tokens, OAuth, and identity providers like IdentityServer. Authorization policies and role-based access control are typically configured using the Authorize attribute.

----------------------------------------------------------------

8. What are the benefits of using ASP.NET Core for web development?

Answer:

• Cross-Platform: Develop on Windows, macOS, and Linux.
• High Performance: Improved speed and scalability.
• Unified Framework: Consistent development model for web and cloud applications.
• Modular: Lightweight, modular framework with NuGet packages.
• Community Support: Open-source with strong community and Microsoft support.

----------------------------------------------------------------

9. How do you deploy an ASP.NET Core application to a production environment?

Answer: Deployment of ASP.NET Core applications can be done in various ways:

• Docker: Containerize the application and deploy using Docker.
• Cloud Services: Use cloud platforms like Azure, AWS, or Google Cloud.
• IIS: Deploy to IIS on Windows using the Web Deploy tool or manual configuration.
• Self-Hosting: Use Kestrel or other web servers to host the application directly.

----------------------------------------------------------------

10. What is routing in ASP.NET Core and how is it configured?

Answer: Routing in ASP.NET Core is used to map incoming requests to corresponding endpoints (controllers, actions, Razor Pages). It is configured in the Startup.Configure method using the UseRouting and UseEndpoints methods. 

For example:

app.UseRouting();

app.UseEndpoints(endpoints =>

{

    endpoints.MapControllerRoute(

        name: "default",

        pattern: "{controller=Home}/{action=Index}/{id?}");

});

------------------------------------------------------