Top 50 ASP.NET MVC Interview Questions & Answers You Should Prepare in 2021

Top 50 ASP.NET MVC Interview Questions & Answers You Should Prepare in 2021

Are you planning to attend a .NET Interview? In this article, I have listed the top 50 MVC Interview Questions & Answers to help you succeed.

Yash Tiwari
·Aug 25, 2021·

14 min read

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While preparing for a .NET interview, it is necessary to prepare for ASP .NET MVC interview questions too. MVC is a framework for building Web applications using .NET and C#. In this article, I have listed the 50 most commonly asked interview questions about MVC to help you ace your interview round.

ASP .NET MVC Interview Questions & Answers

1. Explain MVC?

Answer: MVC stands for Model, View, and Controller. The MVC architectural pattern splits an application into three main components – Model, View, and Controller. In this pattern, the model represents the data structure and business logic. It maintains and preserves the application's data. In a database, model objects store and retrieve the model state. Essentially, a view is a user interface. The view segment enables the user to see and modify the data-using model. Meanwhile, the controller is responsible for handling the user's request.

2. List out a few different return types of a controller action method?

Answer: The following are the different return types of a controller action method:

  • View Result

  • Javascript Result

  • Redirect Result

  • JSON Result

  • Content Result

3. What are the two ways to add constraints to a route?

Answer: There are two ways to add constraints to a route:

  • Using Regular Expression
  • Using an object that implements IRouteConstraint Interface

4. What are the advantages of MVC?

Answer: MVC offers the following advantages:

  • With MVC, your project is divided into different segments, making it easier for developers to manage.
  • Easily manageable and maintainable.
  • It makes your project more systematic.
  • The development takes place in parallel.
  • In MVC, each object has different responsibilities.
  • Classes and objects are independent of one another.
  • It allows a clear separation between business logic and presentation logic.
  • With fewer development and maintenance costs for your project, you can easily edit or change some parts of it.

5. What is the difference between adding routes to a webform application and an MVC application?

Answer: We use the MapPageRoute() method of the RouteCollection class to add routes to a webform application. Likewise, we use the MapRoute() method to add routes to an MVC application.

6. How to maintain sessions in MVC?

Answer: In MVC, we can maintain sessions in three ways:

  1. temp data
  2. viewdata
  3. view bag

7. What is the role of "ActionFilters" in MVC?

Answer: MVC's ActionFilters allow you to execute logic while the MVC action is executed or it is executing.

8. What is the role of components Presentation, Abstraction, and Control in MVC?

Answer: Components Presentation, Abstraction, and Control play the following role in MVC:

  • Presentation: As the name suggests, it is the visual representation of a particular abstraction in the application.
  • Abstraction: It is the business domain functionality present in the application.
  • Control: As well as communicating with other controls within the system, it is a component that maintains consistency between the abstraction within the system and their presentation to the user.

9. What are the drawbacks of the MVC model?

Answer: MVC model has some important drawbacks:

  • The model pattern is a little complicated.
  • The sluggishness of data access in view.
  • MVC is difficult to use with a modern user interface.
  • Parallel development requires multiple programmers.
  • Knowledge of multiple technologies is required.

10. What "beforeFilter()","beforeRender" and "afterFilter" functions do in Controller?

Answer:

  • beforeFilter(): This function runs before every action in the controller. It's the right place to check for an active session or inspect user permissions.
  • beforeRender(): This function is called after controller action logic, but before the view is rendered. This function is not often used but may be required if you are calling render() manually before the end of a given action.
  • afterFilter(): This function is called after every controller action and after rendering is done. It is the last controller method to run.

11. What is Routing? What are its three segments?

Answer: Routing is a process in which you can select a URL structure and map the URL to the controller. For routing, it is important to consider the following three segments:

  • ActionMethodName
  • ControllerName
  • Parameter

12. How Routing works in MVC pattern?

Answer: Among the registered routes in the application, there is a group of routes called the RouteCollection. In this collection, the RegisterRoutes method records the routes. Routing defines a URL pattern and a handler to use if the request matches the pattern.

The first parameter of the MapRoute method is the route name. The second parameter is the pattern to which the URL matches. If placeholders are not defined, then the third parameter might be the default value.

13. Name the assembly in which the MVC framework is typically defined.

Answer: The MVC framework is generally defined in System.Web.Mvc.

14. What is the difference between Temp data, View data, and View Bag?

Answer: As explained above, we maintain sessions in MVC in three ways - Temp data, View data, and View Bag. Here's the difference between these three:

  • Temp data: It assists in maintaining data while switching between controllers.
  • View data: It helps in maintaining data between controllers and views.
  • View Bag: A dynamic wrapped around view data.

15. What is the MVC Application life cycle?

Answer: Every web application goes through two steps during execution, first understanding the request and then sending out the appropriate response, depending on the type of request. There are two main phases in the MVC application life cycle: creating the request object and sending the response to the browser.

Four basic steps are involved in creating the request object:

  • Fill route
  • Fetch route
  • Request context created
  • Controller instance created

16. How can you implement Ajax in MVC?

Answer: We can implement Ajax in two ways in MVC:

  • Jquery
  • Ajax libraries

17. What is a partial view in MVC?

Answer: A partial view in MVC renders a portion of the view content. It reduces code duplication. Simply put, the partial view facilitates the rendering of a view within the parent view.

18. What are the Filters?

Answer: At times, we want to execute specific logic either before or after an action method is executed. In such cases, we can use Action Filter. Filters define the logic that happens before or after an action method is executed. Action Filters are attributes we can assign to the action methods. The MVC action filter types are as follows:

  1. Authorization Filter
  2. Action Filter
  3. Result Filter
  4. Exception Filter

19. Can you explain the page life cycle of MVC?

Answer: Below are the steps that define the page life cycle.

  • App initialization
  • Routing
  • Instantiate and execute controller
  • Locate and invoke controller action
  • Instantiate and render view.

20. Explain the concept of Default Route in MVC

Answer: The default ASP .NET MVC project templates include a general route with the following URL convention to split the URL for a given request into three named segments.

URL: "{controller}/{action}/{id}"

The route pattern is registered by calling the MapRoute() extension method of RouteCollection.

21. What are GET and POST Action types?

Answer:

  • GET Action Type: GET requests data from a specified resource. In all GET requests, we pass the URL, which is mandatory, but it can cause the following overloads.
  • POST Action Type: Using a POST, you can submit data to a resource to be processed. With every POST request, we pass the URL, which is essential, and the data. However, it can handle the following overloads.

22. Mention the Benefits of Area in MVC

Answer: Area in MVC has the following benefits:

  • Easy for unit testing
  • You can easily integrate it with other areas created by others.
  • It lets us organize models, views, and controllers into different functional sections of the application, like administration, billing, customer support, and much more.

23. Explain the concept of Razor in ASP .NET MVC?

Answer: ASP .NET MVC has always supported the concept of view engines – pluggable modules that support different template syntaxes. By default, ASP .NET MVC uses the same .aspx/.ascx/.master file templates as ASP .NET WebForms. A few other popular MVC view engines are Spart & Nhaml. Razor is a new view engine introduced by MVC 3.

24. What are two instances where routing is not implemented or required?

Answer: There are two instances where routing is not required:

  • If a physical file is found that matches the URL pattern.
  • Incase routing is disabled for a URL pattern.

25. What do you mean by MVC Scaffolding?

Answer: For ASP .NET Web applications, scaffolding is a code generation framework. Pre-installed code generators are available for both MVC and Web API projects in Visual Studio. If you need to add code that interacts with data models quickly, scaffolding is the way to go. By using scaffolding, you can reduce the amount of time it takes to develop standard data operations.

It includes page templates, entity page templates, field page templates, and filter templates. They are known as scaffold templates, which help you quickly create a data-driven website.

26. What is Database first approach in MVC using Entity Framework?

Answer: Database First Approach offers an alternative to the Code First and Model First approaches to the Entity Data Model. The Entity Data Model generates model codes (classes, DbContext, etc.) from the database in the project, and that class acts as the link between the database and the controller.

To connect a database with an application, there are several approaches.

  • Database First
  • Code First
  • Model First

27. Which class will you use for sending the result back in JSON format in MVC?

Answer: In an MVC application, you must implement the "JSONRESULT" class to return results in JSON format.

28. What is TempData in MVC?

Answer: TempData is a dictionary object used to store data temporarily. It is MVC's TempDataDictionary class that acts as a controller base-class's instance property. You can store data for an HTTP request in TempData.

29. What was the need to introduce WebAPI technology?

Answer: As we know, HTTP is the most-used protocol. Over the years, the browser was the go-to client for consuming data exposed over HTTP. Nevertheless, as the years went by, the client variety broadened. We requested that clients such as mobile, JavaScript, and Windows applications consume data over HTTP.

Hence, REST provided a way to satisfy a wide range of clients. With WebAPI, you can expose data over HTTP based on REST principles.

30. Which is more preferred? Razor or ASPX?

Answer: Based on the research made by Microsoft, Razor is the best and most preferred method over ASPX because it is lightweight and offers a simple syntax.

31. Explain briefly what you understand by separation of concern.

Answer: Separation of Concerns is a core feature and benefit of using MVC and is supported by ASP .NET. Furthermore, MVC provides decoupling of concerns such as User Interface (UI), data, and business logic.

32. Why are Minification and Bundling introduced in MVC?

Answer: The MVC framework includes two new techniques, Bundling, and Minification, whose primary purpose is to reduce the time it takes for a request to load. The load time is sped up by reducing the number of requests sent to the server as well as by reducing the size of the requested assets (JavaScript and CSS).

33. How does View differ from Partial View in MVC?

Answer: View and Partial View differ in the following major ways:

ViewPartial View
View is less lightweight than Partial viewUnlike View, Partial View is lightweight.
Have its own layout page.It doesn't have its own layout page.
The Viewstart page is rendered prior to rendering any view.Partial view is built particularly for rendering in the view.
The view may contain markup tags of HTML like HTML, head, body, title, meta, etc.It does not contain any markup.

34. Mention the significance of NonActionAttribute?

Answer: The several public methods bundled with the controller class constitute to be the action method. To prevent the default method, you must allocate its public method with the NonActionAttribute.

35. What is ViewStart?

Answer: Razor View Engine introduced a new layout called _ViewStart, which is applied to all views automatically. A ViewStart function is run first, followed by the start rendering and all other views.

36. Mention the possible file extensions used for razor views?

Answer: Razor views use the following file extensions:

  • .cshtml: When you use C# as the programming language for your MVC application.
  • .vbhtml: When you use VB as the programming language for your MVC application.

37. How can we implement validation in MVC?

Answer: By using the validators defined in the System.ComponentModel.DataAnnotations namespace, we can easily implement validation in the MVC application. Validators come in various types, including the following:

  • DataType
  • Range
  • Required
  • StringLength

38. Could you briefly explain how ViewModel works in MVC?

Answer: In a nutshell, ViewModel is a plain class with different properties. It is used for binding a strongly-typed view. It includes several validation rules for specifying the properties of practicing data annotation.

39. How will you explain the concept of RenderBody and RenderPage of MVC?

Answer: Essentially, a RenderBody is a ContentPlaceHolder for web forms. It is available on the layout page and is responsible for rendering child pages and views. However, the layout page contains only a single RenderBody() method. Multiple RenderPage() can exist within the Layout page.

40. What are the main Razor Syntax Rules?

Answer: The following are the main rules for Razor syntax:

  • You have to enclose Razor code blocks in @{ … }
  • Code statements end with a semi-colon.
  • C# code is case-sensitive.
  • Enclose Strings with quotation marks.
  • Inline expressions (functions and variables) start with @
  • C# files have the extension .cshtml
  • Variables are declared with the var keyword.

41. Why do we use Html.Partial in MVC?

Answer: The HTML.partial method renders the specified partial view as an HTML string. It does not depend on any action methods. As shown below -

@Html.Partial(“TestPartialView”)

42. How to perform Exception Handling in MVC?

Answer: Exception handling refers to the action taken when exceptional conditions require special handling. In any application, handling exceptions is crucial.

As a controller, you can override the OnException event and set the Result to the view name to be invoked when an exception is thrown.

For example:

public class HomeController : Controller{
protected override void OnException(ExceptionContext filterContext){
Exception ex = filterContext.Exception;
filterContext.ExceptionHandled = true;
var model = new HandleErrorInfo(filterContext.Exception, "Controller","Action");
filterContext.Result = new ViewResult()
{
ViewName = "Error",
ViewData = new ViewDataDictionary(model)
};
}
}

43. What is Code Blocks in Views?

Answer: Code block is used to enclose C# code statements in views. Unlike code expressions that are interpreted and sent to the response, it is code blocks that are executed. This is useful for declaring variables t+hat may be required at a later date.

44. What are Non Action methods in MVC?

Answer: All public methods are treated as Actions in MVC. As shown below, if you want to use a method as a non-action method, it has to be decorated with the "NonAction" attribute.

[NonAction]
public void TestMethod(){
// Method logic
}

45. How do you implement Forms authentication in MVC?

Answer: Authentication is a process of authenticating the user identity for a specific service by using credentials such as username and password or email address and password. In other words, it ensures that the correct user is authenticated or logged in for a certain service and that the appropriate service has been provided to that user accordingly.

Answer: You can navigate using the ActionLink method. The following code creates a simple URL to navigate to the "Home" controller and call the Gotohome action.

<%= Html.ActionLink("Home","Gotohome") %>

47. What is the difference between MVVM and MVC?

Answer:

MVCMVVM
Old ModelRelatively New Model
A controller is the entry point within the application.View is the entry point within the application.
It doesn't have references to the controller.It has references to View-model.
Controller and view have a one-to-many relationship.It has a one-to-many relationship between View and View Model.
MVC is difficult to read, change, unit test, and reuse this model.If the data bindings are complex, the debugging process will be complicated.
You can test the MVC Model component separately from the user.It is easy for separate unit testing and code is event-driven.

48. What is Spring MVC?

Answer: The Spring MVC or Spring Web MVC framework is a framework that implements a "Model View Controller" (MVC) architecture for applications as well as ready-to-use components for developing adjustable and adaptable web applications. It is a Java-based framework designed to build web applications. It uses the Model-View-Controller design approach. Nonetheless, the framework also has all the characteristics of a core Spring Framework, such as dependency injection, lightweight, integration with other frameworks, and inversion of control. With the help of DispatcherServlet, Spring MVC offers a dignified way to implement MVC in Spring Framework.

49. What is DispatcherServlet?

Answer: The dispatcher serverlet is a class that receives incoming requests and maps them to the most appropriate resources, including Models, Views, and Controllers.

Using web.xml, you can map requests that the DispatcherServlet should handle to the URL mapping in the same file.

50. Do you know about Glimpse?

Answer: Yes, Glimpse is useful for finding out performance, debugging, and diagnosing information. With Glimpse, one can gain an understanding of routes, timelines, model binding, etc.


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