MVC Interview Questions

Core MVC Concepts

1. What is MVC?

MVC (Model-View-Controller) is an architectural pattern that separates an application into three interconnected components:

Model: Manages the application’s data and business logic.

View: Presents the data to the user.

Controller: Handles user input and updates the Model and View.

2. Explain the MVC lifecycle.

A user request is routed to the Controller.

The Controller interacts with the Model to retrieve or update data.

The Controller selects the appropriate View and passes the Model data.

The View renders the data and sends the response back to the user.

3. What are the advantages of using MVC?

Separation of concerns: Improves code organization and maintainability.

Testability: Easier to unit test individual components.

Reusability: Models and Views can be reused in different parts of the application.

Parallel development: Developers can work on different components simultaneously.

Routing

4. What is routing in MVC?

Routing is the process of mapping URLs to specific Controller actions.

5. How do you define routes in MVC?

Routes are typically defined in the RouteConfig.cs file using the MapRoute method.

6. What are route parameters?

Route parameters are variables in a URL that capture values, which can be used by the Controller action.

Controllers

7. What is the role of a Controller?

Controllers handle user input, interact with the Model, and select the appropriate View.

8. What are Action methods?

Action methods are public methods within a Controller that respond to specific requests.

9. What are HTTP verbs (GET, POST, PUT, DELETE)?

These verbs define the type of action a request intends to perform.

GET: Retrieves data.

POST: Submits data.

PUT: Updates data.

DELETE: Deletes data.

10. What is ActionResult?

ActionResult is an abstract class that represents the result of a Controller action. Common derived classes include ViewResult, JsonResult, and RedirectResult.

Views

11. What is a View?

A View is responsible for rendering the user interface.

12. What is Razor syntax?

Razor is a markup syntax that allows you to embed C# code within HTML.

13. What are partial views?

Partial views are reusable View components that can be rendered within other Views.

14. What are Layout pages?

Layout pages define the common structure and layout for multiple Views.

15. Difference between ViewData, ViewBag, and TempData.

ViewData: dictionary based data transfer.

ViewBag: dynamic property based data transfer.

TempData: used to pass data between subsequent requests.

Models

16. What is a Model?

A Model represents the application’s data and business logic.

17. What is data validation?

Data validation ensures that user input meets specific criteria.

18. How do you implement data validation in MVC?

Using data annotations or custom validation logic.

19. What is Entity Framework?

Entity Framework is an Object-Relational Mapper (ORM) that simplifies database interactions.

20. What is a ViewModel?

A ViewModel is a class that is designed specifically for a View, containing the data required by that View.

ASP.NET MVC and Web API

21. What is the difference between ASP.NET MVC and ASP.NET Web API?

MVC is for building web applications with user interfaces, while Web API is for building HTTP services that return data.

22. What are RESTful services?

RESTful services are web services that adhere to the principles of REST (Representational State Transfer).

23. How do you implement Web API in an MVC application?

By creating API Controllers that return data in formats like JSON or XML.

Security

24. What is Cross-Site Request Forgery (CSRF)?

CSRF is an attack that forces a user to execute unwanted actions on a web application in which they’re currently authenticated.  

25. How do you prevent CSRF attacks in MVC?

By using anti-forgery tokens.

26. What is authentication and authorization?

Authentication verifies the identity of a user, while authorization determines what resources a user is allowed to access.

Advanced Concepts

27. What are Filters?

Filters are classes that can be executed before or after Controller actions.

28. What is Dependency Injection (DI)?

DI is a design pattern that allows you to provide dependencies to a class from an external source.

29. What is bundling and minification?

Bundling combines multiple files into a single file, and minification removes unnecessary characters to reduce file size.

30. What is asynchronous programming in MVC?

Asynchronous programming allows you to perform long-running operations without blocking the main thread.

IX. Error Handling and Logging

31. How do you handle exceptions in MVC?

Using try-catch blocks within Controller actions and implementing custom error handling using filters or global exception handlers.

32. What is a global exception filter?

A filter that handles unhandled exceptions across the entire application.

33. How do you implement logging in MVC?

Using logging frameworks like log4net, NLog, or the built-in ILogger in ASP.NET Core, to record application events and errors.

34. What are custom error pages?

User-friendly pages displayed when errors occur, improving the user experience.

X. Caching

35. What is caching in MVC?

Storing frequently accessed data in memory to reduce database or server load.

36. What are the different types of caching in MVC?

Output caching (caching the entire response), data caching (caching specific data), and distributed caching (using a shared cache like Redis).

37. How do you implement output caching?

Using the [OutputCache] attribute on Controller actions.

38. What is distributed caching, and why is it used?

It is a cache that is shared between multiple servers. It is used to improve performance and scalability of web applications.

AJAX

39. How do you implement AJAX in MVC?

Using JavaScript libraries like jQuery to make asynchronous requests to Controller actions.

40. What is a JsonResult?

An ActionResult that returns data in JSON format, commonly used for AJAX responses.

41. What are the benefits of using AJAX?

Improved user experience by updating parts of a page without full page reloads.

Unit Testing

42. Why is unit testing important in MVC?

To ensure the correctness and reliability of individual components.

43. How do you unit test Controllers?

By mocking dependencies and verifying the behavior of Action methods.

44. What is mocking?

Creating simulated objects that mimic the behavior of real dependencies.

45. What are some unit testing frameworks used in .NET?

NUnit, xUnit, and MSTest.

Deployment

46. How do you deploy an MVC application?

Using methods like publishing to IIS, deploying to Azure App Service, or using containerization (Docker).

47. What is IIS?

Internet Information Services, a web server from Microsoft.

48. What are deployment pipelines?

Automated processes for building, testing, and deploying applications.

ASP.NET Core MVC Changes

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

Cross-platform support, improved performance, dependency injection built-in, and a more modular architecture.

50. What is middleware in ASP.NET Core?

Middleware components are executed in a pipeline to handle requests and responses. They can perform tasks like authentication, logging, and routing.

By covering these additional areas, you’ll have a much more comprehensive understanding of MVC and be well-prepared for technical interviews.