📌 Series Context: This is the fifth article in the 10‑part series covering the most important areas of .NET interview preparation. In Part 1, we introduced the .NET ecosystem. In Part 2, we covered C# fundamentals.In Part 3, we explored advanced C# features. In Part 4, we discussed ASP.NET MVC. Now, we’ll focus on ASP.NET Core, the modern, cross‑platform successor to MVC.
Why ASP.NET Core?
ASP.NET Core is a cross-platform, high-performance, open-source framework for building modern web applications and APIs. It's designed to run on Windows, Linux, and macOS, making it ideal for cloud-native development.
Interviewers often ask about middleware, dependency injection, configuration, and hosting in ASP.NET Core.
Key Features
Cross-Platform
Unified Framework
Middleware Pipeline
Dependency Injection
Configuration
Middleware Pipeline
ASP.NET Core uses middleware components to process HTTP requests.
Example
public void Configure(IApplicationBuilder app)
{
app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
👉 Interview Tip: Be ready to explain the order of middleware execution.
Dependency Injection
ASP.NET Core has built-in dependency injection. Services are registered in Startup.cs.
Example
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
services.AddScoped<IPatientService, PatientService>();
}
👉 Interview Tip: Be ready to explain Scoped vs Singleton vs Transient lifetimes.
Configuration
ASP.NET Core supports multiple configuration sources:
appsettings.json
Environment variables
User secrets
Example
{
"ConnectionStrings": {
"DefaultConnection": "Server=.;Database=HospitalDB;Trusted_Connection=True;"
}
}
Hosting
ASP.NET Core applications are hosted using Kestrel (the built-in web server).
They can also be reverse-proxied with:
Common Interview Questions (Part 5)
What are the differences between ASP.NET MVC and ASP.NET Core?
Explain the middleware pipeline.
How does dependency injection work in ASP.NET Core?
What are Scoped, Singleton, and Transient lifetimes?
How does configuration work in ASP.NET Core?
Conclusion
In this fifth part, we covered:
The key features of ASP.NET Core.
Middleware pipeline and its execution order.
Dependency injection and service lifetimes.
Configuration and hosting options.
Typical interview questions on ASP.NET Core.
This foundation prepares you for Part 6, where we'll explore Entity Framework & Data Access—covering LINQ, migrations, and performance tips.
Summary
ASP.NET Core is a modern, cross-platform framework designed for building high-performance web applications and APIs. Understanding its middleware pipeline, dependency injection system, configuration sources, hosting options, and service lifetimes is essential for both real-world development and .NET interview preparation.