Top 60 ASP.NET Interview Questions and Answers in 2025

Why .NET Skills in Demand for Software Developers?

.NET skills are widely needed for getting hired as software developers owing to the following reasons: 

Wide Compatibility: The .NET software works well with any platform being used for building applications, easing professionals’ ability to carry out tasks. The generated applications are compatible with functionality in different operating systems such as Windows, cloud solutions, iOS, Android and others. 

Performance: .NET is known for producing responsive outcomes and reliability at effective speed. The feature allows learning and experimentation for better understanding. 

Popularity: The .NET framework has received multiple updates, with version 8 being released in November 2023. The updates, improvements, and progress have led to its wide adoption among organizations. 

Support: .NET supports around 60 languages, ensuring ease of usage for the software developers. Further, additional support for quick functionality is available to the professionals via resources, tools, frameworks and library classes for web application development. 

Cost-effectiveness: The integrated development environment further contributes to the widescale adoption of .NET, enhancing its importance. Allowing scalability, it also exhibits flexibility in handling hardware and software scaleups without complicated technicalities. 

Broad integration: The .NET integrates with many applications such as databases, services and existing systems. The integration contributes to its high demand, enhances the data exchange and smoothens the workflow, easing the task.

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Basic ASP.NET Interview Questions 

1. What is ASP.NET?

ASP.NET is a server-side technology used for developing dynamic websites and web applications on the internet. It also produces data-driven web applications.

Microsoft released ASP.NET in 2002 to build dynamic websites and web applications using the .NET framework.

2. What platform does ASP.NET use?

ASP.NET is a cross-platform that works on the .NET framework and runs on Linux, Windows, macOS, and Docker.

3. What is the ASP.NET Life Cycle, and list the types of Life Cycle?

When ASP.NET pages run, it goes through several life cycle steps, which perform a series of actions like initialization, running, restoring, and rendering.

Life Cycle is classified into two categories.

1. Application Life Cycle: The user requests to access the application.
2. Page Life Cycle: The cycle has phases like initialization, restoring, execution, and page rendering. 

4. What is MVC?

MVC is a software architectural pattern that divides an application into three main parts: Model, View, and Controller.

Model: The model helps to create the application’s data domain and represents the application’s public properties and business logic.

View: View represents the data tables, charts, and diagrams by collecting the data from the model.

Controller: The controller helps handle user interactions and controls the flow of the application.

5. List the languages used for ASP.NET

ASP.NET uses object-oriented programming languages that provide a framework and patterns, which are easy to use.

Languages used by ASP.NET Framework are :

C#

C-Sharp is a programming language developed by Microsoft that runs on the .NET framework.

It is used to develop web applications on the .NET framework.

VB.NET

VB.NET is a modern object-oriented programming language developed by Microsoft to combine the features of CLR and .NET.

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6. What type of Library is used in ASP.NET?

A library is a pre-coded Object-Oriented Programming template collection used to develop web-based and desktop applications in ASP.NET. 

ASP.NET uses a Web Library to develop web applications.

7. What is CLR?

CLR is the basic Common Language Runtime virtual machine component of the .NET framework used to run the code. It manages and executes .NET programs. And implements a Virtual Execution System (VES) internally.

Services provided by CLR

• Verification
• Garbage collection
• Security
• Memory management

8. What is IIS? And why do you use it?

Internet Information Server (IIS) is the most popular web server used to host and provide internet-based services to ASP.NET and ASP Web applications.

IIS has its process engine to handle the requests. Using an IIS computer can work as a web server and provide functionality for deploying ASP.NET web applications. It is also responsible for responding to users’ requests.

9. List types of Application Life Cycle.

Application Life Cycle is of five types:

• Application Start: Application Start is a method you execute when a user requests.
• Object Creation: Object Creation contains all the information about current requests and browsing information.
• HTTP Application: HTTP Application processes all subsequent requests sent to the application.
• Dispose: Dispose is responsible for releasing manually unwanted resources.
• Application End: Application End helps to unload the memory of an application.

10. List the advantages of using ASP.NET

ASP.NET is a development framework used for developing web applications. It is one of the most preferred web development technologies at present.

There are a lot of benefits of using ASP.NET. Here are some advantages:

• Applications created using ASP.NET show better performance
• ASP.NET provides multi-development modes for the applications
• Applications created using ASP.NET can be used across the globe
• ASP.NET is language-independent

11. What is an Active Server Page?

Active Server Page is an HTML page used to develop dynamic web pages. It includes one or more scripts on the Microsoft web server before sending the request to the user.

ASP was first released in December 1996. It is used to generate the content that is sent to the client web browser via HTTP response.

12. Describe Web Forms?

Web forms are web pages that a user requests using a browser. It is built using ASP.NET technology. 

It executes on the server and generates output to the browser. It also allows you to add and create custom controls.

Now, have a look at some custom controls provided by ASP.NET.

• Label
• TextBox
• Button
• Hyperlink
• ImageButton

13. What is a Solution Explorer?

Solution Explorer displays a project’s folder and files that appear on a physical hard drive.

14. List the components of ASP.NET.

ASP.NET provides data-driven web applications on the internet using various components.

They are:

• Common Language Runtime
• Language
• Library
• Common Type System
• Windows Forms

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

16. What type of protocol is used to call web service?

Web service is a web-based functionality accessed by using protocols. It uses XML to exchange the software using common internet protocols.

Web service in asp.net has three aspects, they are:

• Creating web service
• Creating a proxy
• Consuming the web service

The HTTP protocol is used in ASP.NET to call a Web Service.

17. Explain the uses of Global.asax

Global.asax handles high-level applications like Application_Start, Session_End, and Session_Start. 

Global file is also used to execute the application-level events and set application-level variables.

Now, you will see some intermediate-level .NET Interview Questions and Answers.

18. What is a Web Library?

A Web Library is a part of a website that accesses all libraries from the browser and helps add collections online.

• It contains base and user-defined data types
• Access to data
• Supports the creation of web services

19. Describe a View State.

View State is a Page-Level State Management technique that is used to preserve the values of the page and controls.

View state contains the following sections:

• Features
• Background
• Scenario
• Class Reference

20. What is a Multi-View?

Multi-View is a parent control for the View. It is used to control all types of views.

Multi-View has the prefix mv.

Syntax:

21. What is Early Binding?

Early Binding is used to check the methods and properties during compilation. It is fast and easy to code and also reduces the compilation time. It also reduces the time needed to identify errors.

Example:

class Simplilearn
{
public string name;
public int roll no;
public void details(string name, int roll no)
{
this.name = name;
this.roll no = roll no;
Console.WriteLine("My name is :" + name);
        Console.WriteLine("My roll no is: " + roll no);
}
}
class Simplicode
{
public static void main(String[] args)
{
Simplilearn s= new Simplilearn();
get.details(“Kumar”, 20);
s.mymethod();
}
}

22. What is Late Binding?

Late Binding takes more time to compile. It is hard to find out the object through Late Binding. Late Binding has dynamic objects and is achieved by virtual machines.

Example:

class Simplilearn
{
public static void main(String[] args)
{
dynamic DynObj =10;
Console.WriteLine(DynObj.GetType());
}
}

23. How is ASP.NET different from ASP.NET Core?

ASP.NET is used to build applications for Windows, where ASP.NET Core is used for Windows, macOS, and Linux.

24. What is Caching?

Caching is a technique used to sort the user data or information in memory. It boosts the performance of the applications and creates pages automatically. 

Caching is also essential for data-related transactions.

25. What is the role of Page Directives?

Page directives describe the attributes of the specific page file for the compiler.

Attributes of Page Directives are:

• Buffer: Enables and displays HTTP response
• ClientTarget: Browses the server controls
• ClientName: Specifies the class name of the page
• Debug: Enables or specifies compilation debug
• CodeFile: Specifies the name of the code-behind file

Syntax:

<%@Page Language =”C#” AutoEventWireup=”true”      CodeFile=”Default.aspx.cs” Inherit=”_Default”%>

26. List types of states in ASP.NET?

State in ASP.NET is used to store the information between requests and to retrieve it when required and hold the information.

ASP.NET provides four types of states:

• Application State: It states all collections of web pages and files in a single directory on a web server.
• Cookie State: It stores the information on the client machine.
• View State: It states the state of the web page and its controls.
• Session State: The session state is used to sort the application data.

27. List the sources of data allowed by ASP.NET.

Data Sources are responsible for insertion, deletion, sorting, and updates.

Some of the data sources are allowed by ASP.NET.

• SQL Data Source
• Object Data Source
• Linq Data Source
• Access Data Source

28. List events of Calendar Control

Calendar control is a function used to provide a calendar on a web page. It also enables you to change and move to the previous months and years.

• Displaying Month
• Selecting weeks and days
• Selecting range
• Displaying the days programmatically         

The events of calendar control are three types:

• Selection Changed
• Day Render
• Visible Month Changed

29. What is a Trace?

Tracing enables viewing diagnostic information about a single request at runtime and debugging the application. 

The trace contains features, background, code examples, and class references.

30. How can we add a Style sheet in Visual Studio?

To add a style sheet, open Solution Explorer and right-click on the option, then click on new, and a pop-up will appear to choose.

31. How can a page layout help in ASP.NET?

Page layout provides an overall container for the pages on the website. For example, the Navigation Area and Footer. Page layout also includes the main content. 

32. List the advantages of using HTML Server controls.

HTML Server Controls are the standard HTML controls used to enable server-side processing.

     Some advantages of using HTML Server Controls are:

• HTML Server Control does not possess any mechanism to identify the capabilities of a client browser.
• Coding can be easy by adding the runat=”server” attribute.
• Controls can interact with the Client-Side Scripting.

33. Explain about Event Bubbling.

Data-bound controls use event bubbling. When a parent control contains child controls, and when an event occurs in child controls, it bubbles the event to the parent; this is called Event bubbling.

Event Bubble is classified into two categories:

• OnBubbleEvent: Handles the event data.
• RaiseBubbleEvent: Sends the event data.

34. List the most common built-in objects of ASP.NET?

Built-in objects access the information from the web server. It is also responsible for recognizing the client accessing the web page. 

Some common built-in objects of ASP.NET are:

• Session: Describes the methods and properties of the objects and stores the information related to the user.
• Context: Describes wrapper for the object.
• Application: Describes the methods and properties of the objects and stores the information related to the web application.
• Request: Describes the methods and properties of the objects and stores the information related to the HTTP requests.
• Server: Describes the methods and properties of the objects from various servers.
• Response: Describes the methods and properties of the objects and stores the information related to the server response.

35. List types of Caching.

Caching is a technique used to sort the user data or information in memory.

Caching is divided into three types:-

• Output Caching: It specifies the duration of the cache and the attribute.
• Fragment Caching: It is a user control caching used in a basic web form page.
• Data Caching: It is used to cache the data of data source controls.

36. What are Breakpoints?

A breakpoint helps to specify the runtime to run a line of a line and stop the execution. It is used to examine and perform various debugging functions and methods.

Example: 

using namespace std;
     { 
     class Breakpoints
     { 
     static void main(string []args)
     {
     int a=3, b=5, c=20;
    int d = a + c - b;
    Console.WriteLine(d)
       }
      }
     }

ASP.NET Interview Questions For Experienced

Now, you will see some advanced Dot Net Interview Questions and Answers.

37. List five web controls in ASP.NET

Web Controls are HTML elements used for script tagging and web form and page functionality. They are:

• HTML Controls
• HTML Server Controls
• User and Custom Controls
• ASP.NET Server Controls
• ASP.NET Ajax Server Controls

38. What are Button controls?

Button controls in ASP.NET display a push button on a web page.

     Syntax:- 

             

     Buttons are divided into three types, they are:

• Simple Push Button: Display the text in a rectangular area.
• Link Button: Display text like a hyperlink.
• Image Button: Displays an image.

39. What is a Range Validator and state its syntax?

The Range Validator checks the input values that lie in between the specified ranges.

Range Validator has three properties:

• Type
• MinimumValue
• MaximumValue

Syntax:

             

   ErrorMessage=”1-6″ MaximumValue=”6″ 

   MinimumValue=”1″ Type=”Integer”>

40. What is a Thread Priority?

In multithreading, each thread has its own priority, which is to gain access to CPU resources; whenever a thread is created in C#, it always possesses some priority. 

It is mainly used to set a value.

Syntax:-

              Public ThreadPriority Priority{ get; ser;}

41. What is the role of Postback in ASP.NET?

Postback is a request sent from a client to the server from the page on which the user is working. It posts the complete page back to the server for a new page.

Postback is submitted to a server before processing the page and holds credentials such as verification like usernames and passwords using a database.

42. List the types of Authentication in ASP.NET?

Authentication is a process of ensuring the user’s identity.

It is divided into four types:

1. Form Authentication
2. Windows Authentication
3. Custom Authentication
4. Passport Authentication

43. Define Web Configuration.

Web Configuration is used to describe the properties and behavior of web applications. It also helps to manage settings. Each web configuration file is an XML file containing a set of configuration elements.

44. Explain Client-Side Script events

Client-side script runs on the browser and speeds up the execution of the page.

• onclick: It is used when the control is clicked.
• onfocus: It is used when the control receives the focus.
• onchange: It is used when the value of the control is changed.
• onblur: It is used when the control loses focus.
• onkeypress: It is used when the user presses the key.

45. What is Anonymous Personalization?

Anonymous Personalization helps users personalize the site before identifying themselves.

Example: 

     cookieTimeout=”20000″ cookiePath=”/” cookieRequiresSSL=”false”

cookieSlidingExpiration=”true” cookieprotection=”Encryption”

cookieless=”User”/>

46. What is Form-Based Authentication?

Form-based authentication is used to edit the web configuration files and add a login page to authenticate. It is used for web applications.

Form-based authentication also provides a way to handle authentication using custom logic in ASP.NET applications.

47. Define Configuration files?

Configuration files help to manage the settings of a website. Settings of configuration files are stored as XML files, separate from the application.

Configuration files are of two types:

• Web Configuration: It contains the machine-specific value for all application settings.
• Machine Configuration: It helps to extend, restrict and override the settings.

48. List different types of cookies used in ASP.NET

Cookies are small pieces of information stored on the client side.

    The cookies in ASP.NET are divided into two types:

• Session Cookie: valid for a single session.
• Persistent Cookie: valid for multiple sessions.

49. Explain the difference between custom controls and user controls.

Custom Controls	User Controls
Custom control is designed for a single application.	User control is designed for multiple applications.
Custom control is loosely coupled.	User control is tightly coupled.
User Interface can be changed.	The User Interface is fixed.

50. Explain the difference between Web Configuration and Machine Configuration files.

Web Configuration	Machine Configuration
Web Config is automatically created when an application is created.	Machine Config is automatically installed with Visual Studio.
File inherits setting from the Machine Config.	Only one Machine Config exists.

51. What do you know about Blazor? 

It is the web framework for the development of web user interface components. These components come with two hosting methods, i.e., they can run on both the server and client side. For the server side, it requires running in ASP.NET Core, and for the client side, the requirement is of the browser on WebAssembly-based .NET runtime (Blazor WebAssembly). 

52. What do you know about the Roslyn compiler platform? 

It is the .NET compiler platform that offers open-source compilers and code analysis APIs. Roslyn offers insights into the complete structure of .NET code with details about symbols, syntax trees and semantic information. It is used for analyzing static code, building custom code analysis tools and refactoring and code generation tools. 

53. Differentiate between Stack and Heap. 

Stack offers storage space for temporary variables. Used for static memory allocation, the storage here depends on linear data structure. A heap is a contrasting form that allows dynamic memory allocation. It stores data in a hierarchical structure, i.e., in tree form. 

54. State the design principles of .NET. 

.NET follows SOLID design principles, stated as follows: 

• S stands for Single responsibility principle 
• O refers to the Open-closed principle 
• L refers to the Liskov substitution principle 
• I stands for Interface segregation principle 
• D stands for Dependency inversion principle 

55. What do you know about immediate vs deferred execution in LINQ?

Immediate execution offers instant results with forced execution of the query. Deferred execution, on the other hand, involves a lack of query execution at a specific time. The query is stored in the variable and is executed when the query variable is iterated over.  

56. State the methods to implement generic action in WebAPI. 

The stated task isn’t possible because WebAPI requires prior information on method signatures. 

57. What are the uses of .NET Core? 

It has multiple uses, listed as follows: 

• To create server applications 
• To create microservices from large enterprise application 
• To support microservices for the functioning of cross-platform services with the .NET Core framework 
• To deploy containers for further deployment of those on operating systems 

58. What are microservices, and why are they used in .NET? 

The microservices refer to a design pattern or architectural style that allows building applications with the help of small and independent communicable modules. They are used to build customer-focused applications in .NET. The created applications hold scalability and independent versioning properties. 

59. State the improvements in .NET 8. 

It offers the following improvements: 

• Arm64 performance 
• JIT throughput 
• SIMD 
• Cloud-native 
• Loop and general optimizations 
• Offers support for AVX-512 ISA extensions 
• Codegen struct promotion 
• Garbage collection 
• Hybrid globalization  

60. State the number of inheritances possible with .NET. 

.NET can support only one inheritance. However, it shows a transitive property that allows one to inherit from previous classes.

How Do I Prepare for a .NET Interview?

Capable of wide usage and broad functionality, .NET encompasses multiple concepts. Preparing for the interview must be thorough and based on your personalized strategy. Here are the points that you can use for deciding your plan: 

Strengthen the Fundamentals

The primary aspect judged in any interview is the candidate’s grasp of basic concepts. Learn the same in .NET, where the basics include its framework, core, versions, tools, libraries and different functions. You must also be well-versed in the programming language used in .NET to exhibit fluency in performing the tasks. 

Get Familiar with Interview 

This point encourages you to read the job description. You need to find out two pieces of information: the interview format and the topics of concern for the designation. The interview format will help you prepare for the overall interview, which will go beyond the technical round. It will also include an assessment of behavioral and interpersonal skills. 

The topics of concern for the designation will help you narrow the wide expectations from the interview. Also, get to know about the company to be better prepared. 

Practice for the Interview 

The aim is to tackle the direct and complex questions asked in the interview. Familiarity and practice helps you to curate answers and  customizes you to the art of developing answers. It also assists in finding out the effective approach for answering and enhances confidence. 

Practice the above-listed .net interview questions and previously asked ones specific to the company of interest. You can go for more questions if your preparation schedule allows. Additionally, we emphasize giving mock interviews to get accustomed to the environment and based on the medium of the interview, you may also obtain constructive feedback. 

Top Companies Hiring .NET Developers

Having guided you through dot net interview questions, here is now the list of top companies hiring developers: 

Brainhub

It is a software development agency harboring top software engineering professionals. They build and modernize the software that offers quick, quality and affordable service. Their offerings include the development of mobile apps at low maintenance cost and fast deployment, along with other services like quality assurance, consultation, legacy app modernization, generative AI development and much more. 

Microsoft 

This well-known MNC supports the .NET platform. Hence, the role can include varying types of posts and functions. Generally, they hire professionals to design and maintain applications, write and test codes, data storage integration and others. 

Infosys

Another well-known brand, Infosys, hires .NET developers to design, develop and enhance software solutions using .NET core programming language. Further, they are concerned with offering digital services such as developing AI-amplified marketing suites, enhancing the functionality and architecture of transactional platforms, consulting and others. 

10Pearls 

They are a software development company that deals with technical design, development, and acceleration. They offer .NET-based solutions through their talented team members. The company provides lightweight, progressive, stable and scalable web applications in a .NET environment. They also cater to large-scale mobile app development projects and offer customized solutions as needed. 

Scopic 

Another top software development company offers the services of developing new applications. It offers custom software, web and AI development, cloud solutions, user interface and experience services. Their services expand across all industries. They serve small and medium-sized businesses and hold great experience in the field.

Conclusion

These 60 .NET interview questions and answers would give you an idea of what questions could be asked in the interview and what you need to prepare.

If you plan to learn .NET, consider enrolling in Simplilearn’s Full Stack Java Developer. This comprehensive program will help you master the fundamentals of .NET programming and help you create .NET projects. In the .NET programming certification course, you will be introduced to .NET space and coding with C#, including Visual Studio and Webforms, which will help you excel in your career.

FAQs

1. What is the difference between .NET Framework and .NET Core?

The .NET framework serves only Windows, while .NET Core supports multiple systems. Similarly, the latter lacks a few functionalities in the .NET framework. 

2. Which language is best for .NET development?

C# is the top choice of language owing to its general purpose language, wide usage and great support system. 

3. What should I know about .NET for a full-stack developer role?

Focus on the .NET framework, familiarity with front-end technologies and back-end development are essential to serve the role’s responsibilities.