Today’s technological era, encircled with software products and web applications, has witnessed the development of multiple frameworks and languages. Also, every framework and programming language has some unique and distinctive features. As a result, developers use them to build more robust web applications and services.
This article will introduce you to one of the sturdiest and industry-recognized frameworks called ASP.NET. You will also get aware of career opportunities available in ASP.NET development.
Additionally, this article is beneficial for aspirants appearing for an ASP.NET interview as it lists commonly asked ASP.NET interview questions along with their detailed answers.
What Exactly is ASP.NET?
ASP.NET is one of the extensively used server-side frameworks for building web applications, services, and websites using any supported .NET language. Here, the term ‘server-side’ is an approach that implements scripts on a web server and generates a response concerning a client’s request to a website.
Microsoft’s ASP.NET is an extended version of the Active Server Pages (ASP) technology. It is an open-source framework developed by Microsoft using a Common Language Runtime (CLR). Thus, enabling programmers to use the .NET language to develop the ASP.NET code. In addition, it is compatible to work with Microsoft Windows, macOS, and Linux systems.
Furthermore, there is an extension to ASP.NET called ASP.NET Core. Like the ASP.NET, ASP.NET Core is also a high-performance, cross-platform, and open-source framework. It uses a .NET Compiler Platform, which too is open-source.
Why Opt for the ASP.NET Framework?
Here are some significant reasons why one must opt for an ASP.NET framework for developing web applications and websites.
- ASP.NET is one of the most robust, high-speed, and free-to-use frameworks.
- It supports a wide range of programming languages.
- ASP.NET is developed in a Windows Server environment. Therefore, it requires less configuration and setup than other development frameworks that must be configured and installed separately.
- Applications, services, and websites developed using the ASP.NET framework are efficient and fast.
- The time required for code compilation in ASP.NET requires less time because an application’s source code is translated into an object code, and then the code is executed. Once compiled, the .NET platform can run that code quickly.
- ASP.NET offers auto-deployment and drag-and-drop server control features.
- As this framework is a server-side framework, it will execute the code on the server.
- Applications or services developed using ASP.NET are more secure as they employ Windows Authentication.
Career Opportunities in ASP.NET
Pursuing a career in ASP.NET mandatorily requires a bachelor’s degree in computer science. Also, it would be an advantage if you possess any ASP.NET certification. Some generic certificates to become an ASP.NET developer are Microsoft Certified Solutions Developer, Java Server Pages, i-Net+ Certification, etc.
Here are some essentials to become an ASP.NET developer:
- A strong understanding of ASP.NET MVC.
- In-depth knowledge of databases, including SQL and NoSQL.
- Good analytical skills.
Today, most businesses are making their presence online. Therefore, they need a robust website that offers a great user experience. Also, the burgeoning demand for powerful web applications has led to increasing demand for proficient web developers. Therefore, ASP.NET developers are in great demand today and many reputed businesses and organizations hire them frequently.
30 Top ASP.NET Interview Questions and Answers
This section entirely focuses on commonly asked ASP.NET interview questions. We assume that you possess a basic understanding of various object-oriented concepts, the C# language, and popular front-end technologies.
Moreover, if it is your first time to appear for an ASP.NET interview, these questions will be of great help to you. So, let’s get started!
1. What do you understand from a web application?
Answer: An application that we can access via web browsers, like Google Chrome, Firefox, etc., is called a web application. Alternatively, we can say that an application running on a web server is a web application. Web applications are not analogous to software applications running locally on a device.
Developers use the client-server model to develop web applications, where an off-site server provides requested services to clients. Typical examples of web applications are email programs, like Gmail, Yahoo, etc., and online messaging programs, like Facebook, Twitter, etc.
2. Explain ASP.
Answer: Active Server Pages is the full form of ASP. It is the predecessor to ASP.NET and is also referred to as classic ASP. Moreover, Microsoft developed ASP to allow developers to create user-friendly and robust web pages. Earlier, ASP was an add-on Internet Information Services (IIS).
We can refer ASP to an HTML page consisting of more than one script. ASP is analogous to other scripting languages, such as JSP and PHP. To identify an ASP page, you can observe a browser’s URL. If an URL has a ‘.asp,’ or ‘.aspx’ extension, it is an ASP page.
3. What is ASP.NET?
Answer: ASP.NET is a segment of the .NET framework. It is one of the most powerful and extensively used frameworks for creating web services, applications, and websites. In addition, ASP.NET offers a unified software structure, a programming model, and multiple services to create dynamic web applications for desktops and mobile devices.
Additionally, ASP.NET uses the HTTP protocol to establish a bilateral communication between a browser and a server. The ASP.NET framework supports various programming languages, such as Jscript, C#, J#, and Visual Basic.Net.
4. Tell me something about ASP.NET Core.
Answer: ASP.NET Core is the successor, or you can say the advanced version of the ASP.NET framework. Unlike its predecessor, ASP.NET Core is a cross-platform framework supporting Windows, Linux, and macOS.
It is a programming model that combines two different technologies – ASP.NET Web API and ASP.NET MVC. Additionally, ASP.NET Core supports side-by-side versioning, meaning that various ASP.NET Core versions can exist together on the same server.
5. State the difference between ASP.NET and ASP.
Answer: The most common and significant difference between ASP and ASP.NET is that ASP.NET is a compiled framework, whereas ASP is an interpreted framework. Some other differences between these two frameworks are:
|ASP connects and works with a database using the ActiveX Data Objects (ADO) technology.||ASP.NET connects and works with a database using the ADO.NET technology.|
|The file extension for web pages developed using the ASP framework is .asp.||The file extension for web pages created using the ASP.NET framework is .aspx.|
|It generates web pages using a scripting language.||ASP.NET builds web applications and services using fully-featured programming languages.|
|The error handling technique in ASP is extremely poor.||ASP.NET comes with excellent error handling ability.|
|There are four built-in classes in ASP. These classes are Request, Response, Session, and Application.||There are more than 2000 built-in classes in ASP.NET.|
6. Define the term ‘IIS’, and state its uses.
Answer: The full form of IIS is Internet Information Services. The primary objective of IIS is to offer internet-based services to web applications developed using the ASP.NET framework. Earlier, IIS was known as Internet Information Server.
Following are some key uses of IIS are:
- It helps our PC to work as a web server. In addition, it offers various features to create and deploy web applications on the server.
- IIS can manage the request and response cycle on a web server.
- Additionally, it provides services of FrontPage server extensions and SMTP.
7. List out advantages of ASP.NET Core.
Answer: The ASP.NET framework offers four significant advantages, as explained below:
ASP.NET Core is one of the fastest and robust frameworks used for developing high-grade web applications and services. In addition, Microsoft has developed ASP.NET Core by keeping the performance parameter in mind.
One of the most desirable benefits of the ASP.NET Core framework is that it is not limited to Windows systems. Instead, it is compatible with other operating systems, like macOS and Linux. Unlike its predecessor, an application’s code developed on ASP.NET Core can run on macOS and Linux systems.
Being open-source, ASP.NET Core has helped various organizations and individuals develop sturdy web services and applications. Developers across the globe have contributed their skills and efforts to developing the ASP.NET Core platform.
- Supports New Technologies
ASP.NET enables the use of many state-of-art technologies, like Blazor and Razor Pages, to develop software applications. In addition, it also allows the use of the conventional technology called Model-View-Controller (MVC).
8. Define caching. List out types of caching in ASP.NET.
Answer: Caching is a technique used to store regularly utilized items or data in a particular memory, enabling us to access those items or data immediately whenever required. Therefore, it reduces the extra work required for an application to generate the previously used items or data.
ASP.NET supports five different kinds of caching, as explained below:
- Data Caching
Caching data from a data source is called data caching. If the cache is still active and not expired, and we request data, the cache fulfills our request. On the other hand, if the cache is expired, the data source provides new data to the cache.
- Output Caching
A cache that maintains a copy of HTML pages or different segments of pages that are delivered to a client is called an output cache. Therefore, when other clients request for the same page or segments of a page, there is no need for recreating it. Instead, we can access it from an output cache.
- Class Caching
When web pages or services are executed for the first time, they are compiled into a page class in the assembly. A cache that stores this assembly is called class cache. Therefore, when a web page or a service in the assembly is requested, a class cache is referred.
- Configuration Caching
A configuration file stores information about an application-wide configuration. Therefore, configuration caching means storing an application’s configuration information.
- Object Caching
Storing different objects present on a web page is called object caching.
9. What are validation controls in ASP.NET?
Answer: In any web application or service, validation plays a vital role. It is essential to validate a user’s input before transmitting it to an application’s various layers. Two major reasons to use validation controls in ASP.NET are: validating a user’s input and executing presentation logic.
Here’s an overview of the two types of validation used by ASP.NET:
One of the significant advantages of client-side validation is that it does not postback a page to the server until the client-side validation is implemented successfully. Therefore, this type of validation is beneficial for users.
The server-side validation is advantageous to developers, as it will never fail because it is independent of a scripting language and a browser.
10. What do you understand about the term ‘Postback’ in ASP.NET?
Answer: A process of giving an ASP.NET page to the server for processing is called Postback. The Postback process’s principal goal is to check a specific page’s credentials against various sources. For instance, we can use the Postback process when we need to verify a username and a respective password from a database.
This process is called Postback because the client machine cannot perform the verification of a page. Therefore, a page and its details are posted to the server. There is a property named ‘isPostBack’ to check whether a particular page is posted back to the server or not.
11. Explain a web server.
Answer: A web server can be hardware or software, either working together or individually. Apache, IIS, Lighttpd, Sun Java System Web Server are some commonly used web servers.
In the context of software, a program that receives and accepts requests from various clients and sends back responses to corresponding requests is a web server. The response from a web server can either be static, like an image or a text or dynamic, like the total value of a shopping cart.
12. Explain the MVC architecture.
Answer: It is an architectural design that separates an application into three different components. MVC is an acronym for Model-View-Controller. The three components that it focuses on are, namely model, view, and controller.
Each component in MVC has its specific and well-defined role. The first component, i.e., model, maintains the business logic and data. C# classes are used in ASP.NET to represent models. View only displays data, i.e., it represents an application’s UI logic. Lastly, controllers manage and respond to users’ input. Based on users’ information, controllers decide which model suits best to which view.
The primary objective to use the MVC pattern is to distribute the responsibility among different components, making an application’s development easier.
13. Name the parent class of all web server controls.
Answer: All web server controls’ parent class is System.Web.UI.Control.
14. What is the HTTP protocol?
Answer: An application-layer protocol, HTTP is used for transferring hypermedia documents. Alternatively, the HTTP protocol facilitates the retrieval of resources like HTML documents. Its full form is Hypertext Transfer Protocol and acts as the basis for data communication on the Web.
The HTTP protocol’s principal objective is to manage communication between web servers and web browsers. Moreover, it follows a client-server architecture. In the HTTP protocol, a client establishes a connection and transmits a request to the server. Furthermore, it waits until it gets back a response from the server.
15. State the differences between the GET() and POST() methods.
Answer: The GET() and POST() methods are the HTTP request methods. However, HTTP supports various methods, like PUT, DELETE, PATCH, COPY, GET, OPTIONS, etc., to transmit data or perform different server operations.
The below table illustrates significant differences between GET() and POST() HTTP request methods.
|The GET() method requests data from a particular resource, such as an API URL.||The POST() method transmits data to a specific resource, like an API URL, to process it.|
|All relevant data is present in the request’s URL.||All relevant information is present in the request’s header.|
|The GET() method supports the URL with a limited length, as specified or supported by a browser.||There are no limitations on the URL’s length.|
|We can bookmark the GET() request.||We cannot bookmark the POST() request.|
|The GET() request is less secure.||The POST() request is more secure than GET().|
|We can cache the GET() request.||We cannot cache the POST() request.|
16. What are session and application objects?
Answer: Variables used to store a user’s information are session objects. In addition, session objects maintain each user’s session ID. A session ID for each user is generated when they enter an application and gets deleted when the user exits.
Objects that maintain a page’s data and access variables in an application are application objects. They store all data available across an application.
17. State the difference between file-based and key-based dependencies.
Answer: File-based Dependency
As its name suggests, a user needs to depend on a file stored in a disk in file-based dependency. We can use the file-based dependency when we wish to display the updated data to a client.
One of the most common applications where file-dependency is used is a news website, which displays information stored in a file. But they update the data in the file when they get any breaking news. Therefore, they need to display updated data to end-users.
In the key-based dependency, a user needs to depend on another cached item. We use the key-based dependency when a cache contains several interrelated objects. Therefore, if any one object in a cache changes, we need to update or expire all objects in a cache.
18. Explain dissimilarities between localization and globalization.
Answer: Globalization is the process of developing applications that enables users from across the globe of different cultures or locales to use them. In other words, it is an approach to recognize an application’s part that is different for different programming languages.
On the contrary, localization is the process of adapting a globalized application, which has already been localized, for a specific locale or language. Alternatively, we can say that localization is customizing an application to make it behave according to a specific locale.
19. Explain server-side scripting and client-side scripting. State differences between them.
Answer: Server-side Scripting
A programming approach that develops the code that can run on the server-side is called server-side scripting. In other words, scripting that we can implement on a web server is server-side scripting.
A programming technique to create code that can run on the client-side without requiring the server-side is called client-side scripting.
The below table highlights the significant differences between client-side and server-side scripting:
|Client-side Scripting||Server-side Scripting|
|We use this type of scripting at an application’s front end, allowing users to see it from a browser.||In server-side scripting, an application’s source code is not visible to users or hidden from clients. It is used at an application’s backend.|
|The processing of the client-side script does not involve any server interaction.||We process server-side scripts to communicate with the server.|
|Client-side scripting reduces the server’s load efficiently.||We use server-side scripting to customize web pages and perform dynamic modifications in websites.|
|This type of scripting is less secure, as it is visible to end-users.||It is more secure and protected, as an application’s source code is hidden from users.|
20. Explain binding in ASP.NET and list out its types.
Answer: The C# compiler in ASP.NET performs binding using the .NET framework when we assign an object to an object variable of a particular type. There are two kinds of binding in ASP.NET that are as follows:
It is also referred to as static binding. In early or static binding, methods or properties are checked at a compile-time. Additionally, a compiler is aware of the object type and what methods or properties it holds. Objects in early binding are of static type. Therefore, early binding is easy to code and performs faster. In addition, it reduces run-time errors.
It is also known as dynamic binding. Unlike early binding, the compiler is not aware of the object type and what properties or methods it holds in late binding. Objects in late binding are dynamic in nature. Moreover, we can achieve late binding using virtual methods. Finally, it is relatively slower than early binding.
21. Explain the use of Response.Write() and Response.Output.Write() methods in ASP.NET.
Answer: In ASP.NET, Response.Write() and Response.Output.Write() methods are used to display the output on the screen. However, there is one significant difference between these two methods. We use the Response.Output.Write() method to display the formatted output on the screen, whereas, the Response.Write() method to simply print the normal text.
22. What are different events in a page’s life cycle?
Answer: Each page has eight different events in its entire life cycle. These events occur in a sequential manner, which is as follows:
23. Explain web.config and machine.config in ASP.NET.
Answer: Web.config: Files that contain configuration settings for a specific web application are web.config files. When we create an ASP.NET web application, the web.config file gets created automatically.
Machine.config: Files that contain configuration settings for all websites present on the web server. These files get automatically installed on our system as soon as we install Visual Studio.net. In addition, a server can have only one machine.config file.
24. Define cookies and explain the types of cookies in ASP.NET.
Answer: Any small piece of information stored in a client’s computer is called a cookie. Therefore, when any user visits a website, the web application can read this information stored within the cookie. In addition, cookies are restricted to 4096 bytes in size. ASP.NET involves two different kinds of cookies:
- Persistent Cookies
Cookies that are maintained on a computer’s hard disk and can be accessed by web servers until they are expired or deleted are called persistent cookies.
- Non-persistent Cookies
Cookies that are not saved on a computer’s hard disk and are utilized by a web server until we close the browser are called non-persistent cookies. These cookies are also referred to as in-memory or session cookies.
25. Name the file extension used for web service.
Answer: The file extension used for web services is ‘.asmx.’
26. Explain the terms ExecuteScalar, ExecuteReader, and ExecuteNonQuery.
When a query returns a single value in output, we use ExecuteScalar. However, if the output contains more than one value, ExecuteScalar returns a single value present in the first column of the first row.
We use ExecuteReader for any output with more than one row or column.
When we don’t want any output to be returned from the execution of the SQL statements, we use ExecuteNonQuery. The two most common instances where we can use ExecuteNonQuery are – creating a database and modifying data in a database.
27. Explain the terms HtmlInputCheckBox control and HtmlInputRadioButton control.
Answer: By using the HtmlInputCheckBox control, we can select multiple items from a list. On the other hand, the HtmlInputRadioButton control allows us to choose only a single item from a list of items.
28. What are weak typing and strong typing?
Answer: Strong typing involves the checking of data type at the compile time. Conversely, weak typing consists of the checking of data type at the run time. Therefore, there are no compilation errors in strong typing.
29. Name the method that forces all validation controls to run.
Answer: A method that forces all validation controls to carry out validation in ASP. NET is Page.Validate().
30. List and explain security controls in ASP.NET.
Answer: ASP.NET consists of five security controls that are as follows:
This security control enables users to enter their login credentials as it provides a login capability.
It displays a logged-in user’s name.
This security control displays the status of logged-in users, i.e., whether they are authenticated or not.
It offers a login view based on the chosen template.
This security control sends an email to users that involves a lost password.
The ASP.NET framework is one of the best frameworks for creating web services, websites, and applications. It is a powerful toolkit that offers powerful auto-deployment and drag-and-drop functionalities. In addition, it significantly reduces costs for developing customized web applications.
This article is a guide for aspirants wishing to acquire a job as an ASP.NET developer. We have listed popular ASP.NET interview questions and their detailed answers.
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