Top 50 ASP.NET Interview Questions and Answers For 2021

Top 50 ASP.NET Interview Questions and Answers For 2021

The following article contains the most common ASP.NET interview questions, along with answers and explanations.


13 min read

This article contains the most common ASP .NET interview questions, along with answers and explanations. Keeping these 50 ASP .NET interview questions close at hand can be helpful while preparing for technical interviews and online selection tests during campus placement for freshers or job interviews for professionals.

You can easily attempt the multiple-choice and objective-type questions on ASP .NET after studying these tricky ASP .NET interview questions.

Learn ASP .NET to create dynamic websites, web applications, web services with the best ASP.NET interview tutorials for beginners in 2021.

ASP . NET Interview Questions & Answers

1. What is ASP .NET?

Answer: ASP .NET is an open-source server-side application framework that allows web developers to create dynamic web pages using the .NET framework. Microsoft developed it so that programmers could create dynamic websites, web applications, and web services.

2. Which compiler is used in ASP .NET?

Answer: .NET Framework uses Roslyn as its compiler.

3. What is the ASP .NET MVC framework?

Answer: ASP .NET MVC is a web application framework for the .NET Platform designed for building full-stack web applications with the Model-View-Controller pattern.

4. What is ASP?

Answer: ASP pertains to Active Server Pages. Also called classic ASP. A server-side technology from Microsoft allows users to create dynamic and interactive web pages. Moreover, it uses different scripting languages to create dynamic websites that can run on any browser.

5. ASP .NET is open-source. Explain.

Answer: Microsoft provides the entire .NET server stack in open source, which means it is available for free. In addition to ASP .NET, this includes the .NET compiler, the .NET Core Runtime, Framework, and Libraries so developers can build .NET applications on Windows, Mac, and Linux.

6. What is the difference between the ASP and ASP .NET?

Answer: Between ASP and ASP .Net, the main difference is ASP is interpreted, whereas ASP .Net is compiled. ASP uses VBScript, so when it is executed, the ASP page is interpreted. ASP .NET, on the other hand, utilizes .Net language such as C# or VB .NET, which is compiled to an intermediate language.

7. Which would be the right framework to be used ASP .NET MVC or ASP .NET Web API?

Answer: ASP .NET Web API is an excellent choice for building a server component usable by multiple clients. On the other hand, if the project will serve primarily as a web application, then ASP .NET MVC is the best choice.

8. What is an ASP .NET Web API framework?

Answer: ASP .NET Web APIs are used only for building backend APIs that can be used by multiple clients, from the web to desktop to mobile. Essentially, it forms the server component in the RESTful (Representational State Transfer) architecture.

9. What is IIS? What is its usage?

Answer: IIS is short for Internet Information Services. Microsoft created it to provide Internet-based services to ASP .NET Web applications. Following are the common usage of IIS:

  • You can deploy and develop Web applications on your server using IIS, making it possible to make your computer act like a Web server.
  • On the Web server, IIS handles the request and response cycle.
  • SMTP and FrontPage server extensions are also available in IIS.
  • IIS uses SMTP for sending emails and the FrontPage server extensions for dynamic features, such as form handlers.

10. Briefly Describe Globalization and Localization?

Answer: Globalization is the expansion of business beyond national borders. Understanding the law and regulations of different countries is necessary to create a business environment. Internalization and localization are both parts of globalization.

By making the product appeal to the local community, localization makes a product available for the local market. In addition to translating web pages in the local language, it includes local preferences, culture, and regional aspects.

To run a stable worldwide business, you need both globalization and localization - where you can show customized content based on local preferences and other factors.

They contribute to effective target marketing and a cohesive global strategy.

11. Explain the various modes for the Session state in ASP .NET?

Answer: To store session state, there are different ways:

  • InProc: The session state is kept in the memory on the webserver. This is the default setting.
  • Custom mode: This allows you to specify a custom storage provider.
  • Off mode: Turns off the session state.
  • OutProc: There are two methods for handling this mode:

  • StateServer: The session state is stored in a separate process called ASP .net state service. The application server retains the session state even if it is restarted and is accessible to multiple Web servers.

  • SQLServer: Session state is stored in a database, so it can be preserved even when the Web application is restarted. In a Web farm, multiple Web servers can access the session state.

12. Explain the request flow in the ASP .NET MVC framework.

Answer: The request flow handles the request from the clients and sends it to the server. From the client, a request reaches the controller. Furthermore, a controller plays a crucial role in determining which model to apply to the request, which is then passed to a view, which transforms it and generates a response to be rendered to the client.

13. What is caching? Explain.

Answer: Caching is a technique that facilitates faster access to frequently used items by storing them in memory for quick access.

14. What are the key requirements for caching?

Answer: The key requirements for caching are:

  • The cached response serves your request by using the response already stored in memory.
  • Caching incurs overhead, so you must be very careful when choosing which items to cache.
  • Cached data from a frequently used web form is ideal for caching.
  • If a web form is cached, its server-side content remains frozen, and any changes to that content are not reflected until the cache is refreshed.

15. What is a multilingual website?

Answer: Multilingual websites offer content in multiple languages. In addition to the content, it includes other resources, including date and time, in different languages.

16. What are the advantages of ASP .NET?

Answer: The next-generation technology platform for ASP is ASP .Net. The following features make it superior to ASP:

  • Compiled Code
  • Configuration and Deployment are easy.
  • Highly Scalable
  • Object and Page caching
  • Language Support
  • Strict coding requirements
  • Third-party control
  • User Authentication

17. Name the parent class of all web server control?

Answer: System.Web.UI.Control class

18. How do you identify that the Page is PostBack?

Answer: Post object has a property called "IsPostBack" that lets you determine whether the page has been posted back.

19. What is the use of the "isPostBack" property?

Answer: The "IsPostBack" property of the page object is used to determine whether the page has been posted back or not.

20. What is the difference between trace and debug?

Answer:To debug builds, we use the Debug class. Commonly, the trace class is used for both debugging and releasing builds.

21. What is the concept of Postback in ASP .NET?

Answer: Usually, a PostBack occurs when a user performs an action (such as submitting a form) that sends information from the page to the server via the POST method.

22. Which object encapsulates the state or data of a user?

Answer: Session object

23. What is the difference between early binding and late binding?


  • Early Binding: Early binding calls a nonvirtual method that is decided during compile-time.
  • Late Binding: When the late binding is used, a virtual method is called at runtime.

24. What is the difference between file-based dependency and key-based dependency?


  • File-based dependency: This type of dependency allows you to save a dependency to a file on your computer.
  • Key-based dependency: You depend on another cached item in key-based dependencies.

25. What are the different validators in ASP .NET?

Answer: The ASP .NET validation controls play an important role in validating user input. Input from the user must always be validated before being sent across the various layers of an application. In ASP .NET, there are two types of validation:

  • Client-Side Validation
  • Server-Side Validation

26. What is the difference between server-side scripting and client-side scripting?


  • Server-side scripting: Server-side scripts are executed by the server and interpreted as needed.

  • Client-side scripting: Client-side scripting executes your script immediately in the browser, for instance, when you validate form fields, emails, etc. Typically, client-side scripting is done in VBScript or JavaScript.

27. How to display validation messages in one control?

Answer: The ValidationSummary control allows us to display all validation messages in one control.

28. What is ViewState? Where is ViewState information stored?

Answer: ASP .NET's ViewState feature allows you to store the values of a page before it is submitted to the server. Once the page is posted, data from its ViewState is restored. The ViewState information is stored in HTML hidden field.

29. How to sign out from forms authentication?

Answer: You can use FormsAuthentication.Signout() method to sign you out from forms authentications.

30. Give some examples of web controls.

Answer: Some examples of web controls are:

  • Button
  • Calendar
  • Checkboxlist
  • RadioButtonList
  • DropDownList

31. What is MVC?

Answer: MVC refers to Model View Controller. It is a design pattern that separates business logic and presentation logic. It is used to create highly customized applications.

The Model represents data, the View represents presentation, and the Controller serves as the interface between the Model and View.

32. What do you mean by Role-based security?

Answer: Role-based security is used in almost all organizations, and each role is assigned certain privileges.

  • A particular role is assigned to each user.
  • Privileges as defined by a role limit a user's actions on the system and ensure that he can only do what is allowed by the system.

Answer: On the client-side, cookie stores a small amount of information. In general, there are two types of cookies:

  • Session/Temporary Cookie: valid for one session
  • Persistent Cookie: valid for several sessions

34. What are the built-in objects in ASP .NET?

Answer: Below are the major built-in objects in ASP .NET:

  • Application
  • Context
  • Request
  • Response
  • Session
  • Server
  • Trace

35. What are the differences between the Response.Write() and Response.Output.Write()?

Answer: Normal output is handled by Response.Write(), whereas the formatted output is handled by Response.Output.Write().

36. Describe the disadvantage of cookies.

Answer: Here are some disadvantages of cookies are:

  • Cookies can store a small amount of data.
  • Cookies can store only string values.
  • Cookies are not secure.
  • Cookies are browser-independent.

37. What are the types of Authentication in ASP .NET?

Answer: ASP .NET supports three types of authentication:

  • Windows Authentication: Built-in windows security features are used to authenticate users.
  • Forms Authentication: Authenticates against a custom list of users or a database of users.
  • Passport Authentication: Verifies against the Microsoft Passport service, which provides a centralized authentication service.

38. What is the difference between a page theme and a global theme?


  • Page Theme: The page theme is applied to specific web pages of the project. It is located inside a subfolder of the App_Themes folder.
  • Global Theme: All web applications on the webserver using the Global theme. Themes are stored in the Themes folder on a Web server.

39. How would you turn off cookies on a page of a website?

Answer: Below are the steps you need to follow:

  • Use the "Cookie.Discard" property.
  • The server sets or gets the discard flag.
  • By setting this property to true, the client application is instructed not to save the Cookie on the hard disk of the user at the end of the session.

40. What is a web service?

Answer: .NET Web services are components that reside on Web servers and provide information and services to other network applications using standard Web protocols like HTTP and Simple Object Access Protocol (SOAP).

41. What are the HTML server controls in ASP .NET?


  • HTML server controls are similar to HTML elements that we use in HTML pages.
  • In HTML server controls, properties and events are exposed for use.
  • In order to make these controls programmatically accessible, we specify that they act as server controls by adding the runat="server" attribute.

42. What is ASP .NET AJAX?

Answer: ASP .NET AJAX is Microsoft's implementation of AJAX functionality. AJAX stands for Asynchronous JavaScript and XML. It is a technology that speeds up response times and reduces traffic between clients and servers. It comes with reusable AJAX controls and is a set of extensions to ASP .NET.

43. ASP .NET is cross-platform Explain.

Answer: ASP .NET applications can be developed and run on any operating system, including Windows, Linux, macOS, and Docker. Therefore, it is called a Cross-platform framework.

44. What is the difference between session and application object?

Answer: Session objects differ from application objects in that all users share the same application object, while session objects are unique to each user. Data in the application object is shared among all sessions of the application. The application object stores data in key-value pairs. In session objects, information is stored specific to the current session and is visible only within that session. For every session of the application, ASP .NET creates a unique SessionId. The application's configuration settings determine whether sessions are maintained by an HTTP cookie or a modified URL. SessionID values are stored in cookies by default.

45. What is ASP .NET Core?

Answer: ASP .NET Core is an open-source, cross-platform version of ASP .NET. Before ASP .NET Core, ASP .NET only existed for Windows platforms. It is typically referred to as "ASP .NET.".

46. What is Razor in ASP .NET?

Answer: Razor is a markup language that allows you to embed server-based code (Visual Basic and C#) in web pages. While the server-based code creates dynamic web content on the fly, a web page is written in the browser. When a web page is requested, the server executes the server-side code inside the page before returning it to the browser. By running on the server, the code can perform complex tasks, such as accessing databases. Razor is a framework for creating web applications based on ASP .NET. While it is easy to learn and easy to use, ASP .NET markup boasts similar power.

47. What is fragment caching?

Answer: Caching of individual user controls within a Web Form is called fragment caching. Each user control can select how the caching behavior will be applied and the duration of the cache. When you need to cache only parts of a page, fragment caching is useful.

48. What is the REST architecture?

Answer: REST (Representational State Transfer) is an architectural style for designing applications that uses HTTP for communications instead of the more complex CORBA, RPC, or SOAP mechanisms. REST is based on a few principles:

  • All things are resources, i.e. File, Images, Video, WebPage, etc.
  • Use clear and uniform Interfaces.
  • Each resource has a unique identifier.
  • All requests should be independent and should be stateless.
  • Everything is done via representation (sending requests from a client to a server and receiving responses from the server to a client).

49. What does the method Finalize do in ASP .NET?

Answer: Finalize performs cleanup operations on unmanaged resources held by an object. It queues an object for finalization. After that, a garbage collector will collect and clean up the Object.

50. What is a Repeater Control and what are the templates supported by the Repeater?

Answer: A Repeater is a Data-bound control. A data-bound control is a container control. To display the data, it creates a link between the Data Source and the presentation UI. Repeater controls display a list of items repeatedly. There are five inline templates for formatting a Repeater:

  • Shows Header text for a Data Source collection and sets a specific style for the Header text.
  • Displays the footer element for the Data Source collection.
  • The Data Source collection defines how each item is rendered.
  • Alters the background color or style of alternating items in a Data Source collection.

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