Top 25 .Net Core Interview Questions and Answers for Experienced Professionals

In this .Net core tutorial explains, I have added a few .Net core interview questions and answers for experienced professionals.

As the technology landscape evolves, so does the demand for professionals with expertise in current technologies such as .NET Core. If you’re an experienced professional in .NET Core, chances are you’re looking to step up your game and face more challenging roles in your career. In the following section, we’ll explore some advanced .NET Core interview questions and answers for experienced professionals.

Table of Contents

.Net Core Interview Questions and Answers for Experienced Professionals

Q-1: What is .NET Core?

.NET Core is an open-source, cross-platform framework for building modern, cloud-based, and internet-connected applications. It’s developed by Microsoft and the .NET community on GitHub and can run on Windows, Linux, and macOS.

Q-2: What is the difference between .NET Framework and .NET Core?

The .NET Framework is a Windows-only component for building applications, while .NET Core is cross-platform, supporting Windows, Linux, and macOS. .NET Core is modular, meaning that instead of assemblies, developers deal with NuGet packages.

Q-3: What are the main characteristics of .NET Core?

.NET Core is cross-platform, supports side-by-side versioning, can be containerized, and has a unified programming model with .NET Standard.

Q-4: What is the .NET Standard?

.NET Standard is a formal specification of .NET APIs that are intended to be available on all .NET implementations. It’s a standard library that any .NET platform has to implement. This unifies the .NET platforms and prevents future fragmentation.

Q-5: Can you explain the difference between ‘AddSingleton’, ‘AddScoped’, and ‘AddTransient’

These are service lifetimes in .NET Core’s dependency injection container:

  • AddSingleton’: Creates a single instance of the service for the entire application and reuses it.
  • ‘AddScoped’: Creates a new instance of the service for each new request or scope.
  • ‘AddTransient’: A new instance is created every time the service is requested.

Q-6: What are some features of Kestrel web server?

Kestrel is a cross-platform web server for ASP.NET Core. It’s the default server that comes with .NET Core applications. It’s designed to be fast, lightweight, and can be used as an edge server.

Q-7: What is Razor Pages in ASP.NET Core?

Razor Pages is a new feature in ASP.NET Core that makes coding page-focused scenarios easier and more productive. It follows the MVVM (Model-View-ViewModel) design pattern.

Q-8: How does .NET Core support the microservices architecture?

.NET Core provides a lightweight, cross-platform, and high-performance framework that’s ideal for microservices. It allows running microservices in Docker containers and Kubernetes for orchestration, and also supports RESTful services via ASP.NET Core Web API.

Q-9: What is Middleware in the context of ASP.NET Core?

Middleware components are software units that handle requests and responses in ASP.NET Core applications. They form a pipeline through which every request must pass. Middleware components can handle aspects like authentication, routing, session management, and more.

Q-10: What is dependency injection in .NET Core?

Dependency Injection (DI) is a design pattern used in .NET Core to achieve Inversion of Control (IoC) between classes and their dependencies. It allows injecting objects into a class, instead of creating them there, which leads to better modularity and less tightly coupled code.

Q-11: Can you explain Entity Framework Core?

Entity Framework Core (EF Core) is a lightweight, extensible, open-source, and cross-platform version of Entity Framework data access technology. It’s an ORM (Object-Relational Mapper) enabling .NET developers to work with a database using .NET objects.

Q-12: What are some ways to improve performance in .NET Core applications?

  • Use in-memory caching or distributed caching.
  • Optimize data access: Use LINQ efficiently, and do not retrieve data that is not needed.
  • Use the latest version of .NET Core: Each version comes with its performance improvements.

Q-13: What is the difference between ‘appsettings.json’ and ‘secrets.json’ files in ASP.NET Core?

‘appsettings.json’ is used to store application settings, such as connection strings, logging configuration, etc. These are typically checked into source control. ‘secrets.json’ is used to store sensitive data, like API keys and passwords, that should not be checked into source control.

Q-14: Can you explain how exception handling works in ASP.NET Core?

Exception handling in ASP.NET Core can be done using middleware. The ‘UseExceptionHandler’ middleware is built-in and can catch exceptions, log them, reset the request path, and re-execute the request. The ‘Developer Exception Page’ middleware can also be used to display detailed exception information in a development environment.

Q-15: What is SignalR in the context of ASP.NET Core?

ASP.NET Core SignalR is an open-source library that simplifies adding real-time web functionality to applications. Real-time web functionality is the ability to have server-side code push content to the connected clients instantly as it becomes available, instead of having the server wait for a client to request new data.

Q-16: How can you achieve real-time communication in .NET Core applications?

ASP.NET Core SignalR provides real-time web functionality in applications, enabling server-side code to instantly push content to the clients. SignalR supports WebSockets protocol and falls back to other compatible techniques when it’s not available.

Q-17: What is Swagger and how is it used in .NET Core?

Swagger, also known as OpenAPI, is a tool used for understanding and documenting RESTful APIs. In .NET Core, you can integrate Swagger using the Swashbuckle NuGet package. It creates a JSON schema that stores API documentation and presents it via a beautiful UI for easy understanding.

Q-18: Can you discuss some of the security measures you would put in place when developing a .NET Core web application?

Some of the security measures include:

  • Use of HTTPS and enforcing SSL.
  • Implementing Cross-Site Scripting (XSS) protection and Cross-Site Request Forgery (CSRF) protection.
  • Using the principle of least privilege in database connections.
  • Implementing authentication and authorization effectively using ASP.NET Core Identity.
  • Encrypting sensitive data in configuration files.

Q-19: What is a Host in .NET Core?

A host is an object that encapsulates an app’s resources, such as an ILogger, IConfiguration, and an IHostedService implementation. When a host starts, it calls IHostedService.StartAsync on each implementation of IHostedService that’s found in the service container’s service collection.

Q-20: What are some use cases for using the ‘IOptions’ interface?

The IOptions interface is used to retrieve the settings from the appsettings.json file or other configuration sources. It’s especially useful when you need to access a certain configuration setting multiple times in the code, and the configuration might change, requiring the app to use the new settings.

Q-21: How does .NET Core support containerization?

.NET Core is designed to be cross-platform, lightweight, and modular, which makes it well-suited for containerized environments. Applications can be packaged along with their dependencies into a container, which can be run consistently across different environments.

Q-22: What is the difference between Concurrency and Parallelism?

Concurrency is when two or more tasks can start, run, and complete in overlapping time periods. It doesn’t necessarily mean they’re running at the same instant. Parallelism is when tasks literally run at the same time, like in a multicore processor.

Q-23: What are Async Streams in C# and .NET Core?

Asynchronous streams, introduced in C# 8.0, are a type of stream that can use async-await syntax to work with streams of data. This feature is particularly useful for situations where you have a stream of data that arrives asynchronously (for example, data coming from a cloud platform).

Q-24: Can you explain what Blazor is in the context of .NET Core?

Blazor is a .NET Core-based web framework for building Single Page Applications (SPAs) using C# instead of JavaScript. It enables developers to build full-stack web applications using .NET and WebAssembly (WASM).

Q-25: How can you create a Worker Service in .NET Core?

A Worker Service in .NET Core is a console application that runs as a service, allowing you to perform tasks in the background, like processing CPU-intensive data or communicating with databases and APIs. You can create a Worker Service by using the Worker Service template in the .NET CLI with the following command:

dotnet new worker -n MyWorkerService

This command creates a new Worker Service project in a new directory named MyWorkerService.

The Worker class, derived from the BackgroundService abstract class, is where the background task’s logic is defined. It includes a ExecuteAsync method that is run when the service starts. Here, you can define operations to be performed when the service is running. The Stopping and Stopped methods can also be overridden to define behavior when the service is stopping or has stopped.

.Net Core Interview Questions and Answers for Experienced Professionals
.Net Core Interview Questions and Answers for Experienced Professionals

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