Are you preparing for a .NET Core job interview in 2023? This guide provides a comprehensive list of the top 50 .NET Core interview questions and answers, covering a wide range of topics such as ASP.NET Core, Entity Framework Core, Web API, and more. Whether you’re a beginner or an experienced developer, this guide will help you prepare for your .NET Core interview and increase your chances of landing your dream job.
Top 50 .NET Core Interview Questions And Answers 2023
1. What is .NET Core?
.NET Core is a free and open-source, cross-platform framework for building modern, cloud-based, and scalable applications.
2. What is the difference between .NET Framework and .NET Core?
.NET Framework is a Windows-only framework, whereas .NET Core is a cross-platform framework that can run on Windows, Linux, and macOS.
3. What are the advantages of using .NET Core?
.NET Core has several advantages, including:
– Cross-platform compatibility
– Faster performance
– Open-source and free
– Modular architecture
– Support for microservices architecture
– Support for containerization
4. What is ASP.NET Core?
ASP.NET Core is a web application framework that is built on top of .NET Core. It enables developers to build web applications and APIs that are cross-platform and scalable.
5. What is the difference between ASP.NET and ASP.NET Core?
ASP.NET is a web application framework built on top of .NET Framework, whereas ASP.NET Core is a web application framework built on top of .NET Core. ASP.NET Core is cross-platform, modular, and designed to be lightweight.
6. What is middleware in ASP.NET Core?
Middleware is software that sits between the web server and the application and handles requests and responses. In ASP.NET Core, middleware can perform various tasks such as authentication, caching, logging, and compression.
7. What is the difference between Razor Pages and MVC in ASP.NET Core?
Razor Pages is a simpler web application model that is ideal for small applications, whereas MVC is a more complex web application model that is suitable for large and complex applications.
8. What is the difference between NuGet and npm?
NuGet is a package manager for .NET Core, whereas npm is a package manager for Node.js. NuGet manages packages for .NET Core, while npm manages packages for JavaScript.
9. Can you explain the difference between the .NET Core SDK and the .NET Core Runtime?
The .NET Core SDK includes the .NET Core Runtime as well as tools for building and publishing .NET Core applications. The .NET Core Runtime includes only the components needed to run .NET Core applications.
10. What is DI (Dependency Injection)?
Dependency Injection is a design pattern that helps to decouple components in an application by allowing them to depend on abstractions rather than concrete implementations.
11. What is a singleton in DI?
A singleton is a design pattern that ensures only one instance of a class is created and shared among multiple components in an application.
12. What is a transient in DI?
A transient is a design pattern that creates a new instance of a class every time it is needed.
13. What is a scoped in DI?
A scoped is a design pattern that creates a new instance of a class for every request or operation.
14. What is LINQ?
LINQ stands for Language Integrated Query. It is a set of language extensions that allows developers to query various data sources, including arrays, collections, and databases, using a syntax that is similar to SQL.
15. Could you explain the differences between IQueryable and IEnumerable?
IQueryable is used to query data from a data source that supports querying, whereas IEnumerable is used to query data from an in-memory collection such as an array or a list.
16. What is Entity Framework Core?
Entity Framework Core is an Object-Relational Mapping (ORM) framework that provides a way to access databases using .NET objects. It is built on top of .NET Core and supports multiple database providers.
17. What is the difference between Entity Framework Core and Entity Framework?
Entity Framework is built on top of .NET Framework and only supports Microsoft SQL Server, while Entity Framework Core is built on top of .NET Core and supports multiple database providers.
18. What is Razor syntax?
Razor syntax is Razor syntax is a simple, lightweight syntax used by ASP.NET Core to create dynamic web pages and templates. It is a mix of HTML markup and C# or VB code that allows developers to easily embed code into HTML pages.
19. What are Tag Helpers in ASP.NET Core?
Tag Helpers are a new feature in ASP.NET Core that allow developers to create custom HTML tags that can execute server-side code. They provide a more intuitive and concise way of working with HTML in Razor views.
20. What is the difference between async and await in C#?
Async and await are keywords used in C# to implement asynchronous programming. Async is used to declare a method that performs asynchronous operations, while await is used to await the completion of an asynchronous operation.
21. What is the difference between an abstract class and an interface in C#?
An abstract class can provide implementation details and can have constructors, while an interface can only declare methods, properties, and events, but cannot provide implementation details or constructors.
22. Could you please explain the differences between a struct and a class in C#?
A struct is a value type, and a class is a reference type. Structs are allocated on the stack, while classes are allocated on the heap. Structs are typically used for small, simple types, while classes are used for more complex types.
23. What is garbage collection in .NET Core?
Garbage collection is the automatic process of deallocating memory that is no longer in use by an application. .NET Core includes a garbage collector that manages the memory used by .NET Core applications.
24. What is the difference between a delegate and an event in C#?
A delegate is a type that represents a reference to a method, while an event is a mechanism for signaling that something has happened and for handling the resulting actions. Events are typically based on delegates.
25. What is the difference between a synchronous and an asynchronous operation in .NET Core?
A synchronous operation blocks the calling thread until it completes, while an asynchronous operation allows the calling thread to continue executing while the operation completes in the background.
26. What is the difference between a unit test and an integration test?
A unit test tests a small unit of code in isolation, while an integration test tests how different units of code work together as a system.
27. What is a mock object in .NET Core?
A mock object is a fake object that simulates the behavior of a real object in a controlled way. It is often used in unit testing to test the behavior of code that depends on external dependencies.
28. What is inversion of control (IoC) in .NET Core?
Inversion of control is a design pattern in which the flow of control in an application is inverted, with control being passed from the application to a framework or container. This allows the framework to manage the lifecycle and dependencies of objects in the application.
29. What is a DI container in .NET Core?
A DI container is a framework that manages the dependencies between objects in an application. It allows objects to be created and injected automatically, based on their dependencies and configuration.
30. What is a middleware pipeline in ASP.NET Core?
A middleware pipeline is a sequence of middleware components that handle requests and responses in an ASP.NET Core application. Each middleware component can modify the request or response before passing it to the next component in the pipeline.
31. What is CORS in ASP.NET Core?
CORS (Cross-Origin Resource Sharing) is a security feature in ASP.NET Core that controls which domains are allowed to access resources on the server. It helps to prevent cross-site scripting attacks.
32. What is JSON serialization in .NET Core?
JSON serialization is the process of converting .NET objects into JSON format. It is commonly used for transferring data between web applications and APIs.
34. What is ASP.NET Core SignalR?
ASP.NET Core SignalR is a real-time communication framework that allows bi-directional communication between a server and clients over websockets, long-polling, or server-sent events. It simplifies the development of real-time web applications.
35. What is an ActionResult in ASP.NET Core?
An ActionResult is a type in ASP.NET Core that represents the result of an action method. It can contain data or a view that will be returned to the client in response to a request.
36. What is a View Component in ASP.NET Core?
A View Component is a type in ASP.NET Core that encapsulates a chunk of functionality and returns a view or HTML snippet to be rendered on the page.
37. What is a Razor Class Library in ASP.NET Core?
A Razor Class Library is a type of project in ASP.NET Core that contains Razor views, Razor Pages, and other web-related assets. It can be used as a reusable component in other ASP.NET Core applications.
38. What is the difference between Razor Pages and MVC in ASP.NET Core?
Razor Pages is a lightweight alternative to the MVC pattern in ASP.NET Core. Razor Pages are focused on handling individual pages and their actions, while MVC is focused on creating an entire application with multiple views and controllers.
39. What is the difference between a cookie and a session in ASP.NET Core?
A cookie is a small piece of data that is stored on the client’s computer, while a session is a set of data that is stored on the server and associated with a specific client. Cookies are used to store information that persists between requests, while sessions are used to store information that persists during a user’s session.
40. What is the difference between a stateful and a stateless application?
A stateful application maintains information about the user’s state between requests, while a stateless application does not. In a stateful application, the server must maintain session information and user state, while in a stateless application, the client must send all necessary information with each request.
41. What is a background task in ASP.NET Core?
A background task is a process that runs in the background of an ASP.NET Core application and performs a specific task, such as sending emails or performing database cleanup.
42. What is the difference between a GET request and a POST request?
A GET request retrieves data from the server, while a POST request sends data to the server to be processed. GET requests are typically used to retrieve information, while POST requests are typically used to create or update information.
43. What is the difference between a PUT request and a PATCH request?
A PUT request is used to update an entire resource, while a PATCH request is used to update a portion of a resource. PUT requests require the entire resource to be sent to the server, while PATCH requests only require the portion of the resource that is being updated.
44. What is the difference between a 401 error and a 403 error?
A 401 error occurs when a client attempts to access a resource that requires authentication, but has not provided valid credentials. A 403 error occurs when a client attempts to access a resource that they do not have permission to access.
45. What is the difference between a 404 error and a 500 error?
A 404 error occurs when a client attempts to access a resource that does not exist. A 500 error occurs when an internal server error occurs.
46. What is the difference between a unit of work and a repository in .NET Core?
A unit of work is responsible for managing the persistence of changes to a group of related entities, while a repository is responsible for querying and modifying data for a specific entity type.
47. What is a distributed system in .NET Core?
A distributed system is a software system that is composed of multiple independent components that communicate and coordinate with each other through a network. In .NET Core, distributed systems can be created using technologies such as ASP.NET Core, gRPC, and Azure Service Fabric.
48. What is gRPC in .NET Core?
gRPC is a modern, high-performance, open-source remote procedure call (RPC) framework that can be used to create distributed systems in .NET Core. It uses protocol buffers as its data format and supports bi-directional streaming, flow control, and many other advanced features.
49. What is middleware in ASP.NET Core?
Middleware is a type of component in ASP.NET Core that sits between the server and the application and can perform various tasks, such as authentication, logging, and routing. Middleware is added to the application pipeline and can be chained together to create a request processing pipeline.
50. What is the difference between a factory method and a constructor in .NET Core?
A factory method is a method that is responsible for creating and returning an instance of a class, while a constructor is a method that is responsible for initializing an instance of a class. Factory methods can be used to create objects in a more flexible and configurable way than constructors, and can also be used to create objects that require complex initialization logic.