ASP.Net Intermediate Level Interview Questions & Answers

1. What is ASP.NET and how does it differ from ASP?
   Answer: ASP.NET is a web application framework developed by Microsoft, while ASP (Active Server Pages) is an older technology. ASP.NET offers more features and better performance compared to ASP.
   
   
2. Explain the Page Life Cycle in ASP.NET.
   Answer: The Page Life Cycle in ASP.NET represents the stages a web page goes through from initialization to rendering. It includes events like Page_Init, Page_Load, and Page_PreRender.
   
   
3. What are the different state management techniques in ASP.NET?
   Answer: State management techniques include ViewState, Session, Cookies, and Application state.
   
   
4. Describe the difference between authentication and authorization in ASP.NET.
   Answer: Authentication verifies the identity of a user, while authorization determines what actions or resources a user is allowed to access.
   
   
5. What is the purpose of the Global.asax file in ASP.NET?
   Answer: Global.asax contains application-level events and handlers, such as Application_Start and Application_End, and can be used for application-level configuration.
   
   
6. Explain the differences between server-side and client-side validation in ASP.NET.
   Answer: Server-side validation occurs on the server, while client-side validation is performed in the user’s browser. Both are used to validate user input, but client-side validation provides a better user experience.
   
   
7. What is ViewState in ASP.NET, and why is it used?
   Answer: ViewState is used to persist state information across postbacks. It stores data on the page and allows the server to recreate the page’s state after a postback.
   
   
8. How do you handle errors in ASP.NET?
   Answer: Errors in ASP.NET can be handled using try-catch blocks or by configuring custom error pages in web.config.
   
   
9. Explain the use of caching in ASP.NET.
   Answer: Caching is used to store frequently accessed data or rendered pages in memory, reducing the need to recreate them on each request and improving performance.
   
   
10. What is the difference between user controls and custom controls in ASP.NET? – Answer: User controls are typically used for small, reusable UI components, while custom controls are more complex and are created by extending existing server controls.
    
    
11. How do you secure your ASP.NET application?
    Answer: Security measures include using authentication and authorization, input validation, secure coding practices, and encryption for sensitive data.
    
    
12. Explain the use of the Web.config file in ASP.NET.
    Answer: Web.config is used for configuration settings, including database connections, error handling, and custom settings for an ASP.NET application.
    
    
13. What are ASP.NET Web Services and WCF Services, and how do they differ?
    Answer: ASP.NET Web Services use XML and HTTP to allow different applications to communicate, while WCF (Windows Communication Foundation) is a more comprehensive framework for building distributed systems, supporting various protocols.
    
    
14. What is the role of the App_Code folder in an ASP.NET application?
    Answer: The App_Code folder is used to store source code files, classes, and business logic that can be dynamically compiled at runtime in an ASP.NET application.
    
    
15. How does the ASP.NET authentication model work, and what are its components?
    Answer: ASP.NET authentication uses a combination of authentication modes (Forms, Windows, etc.) and providers (Membership, Role, etc.) to verify user identity and manage access to resources.
    
    
16. Explain the concept of AJAX in ASP.NET.
    Answer: AJAX (Asynchronous JavaScript and XML) allows you to create interactive web applications by making asynchronous requests to the server, updating parts of the page without requiring a full page refresh.
    
    
17. What is the role of the Globalization and Localization features in ASP.NET?
    Answer: Globalization and Localization enable applications to support multiple languages and cultures, allowing for content and user interface customization.
    
    
18. Describe the use of the Entity Framework in ASP.NET.
    Answer: Entity Framework is an Object-Relational Mapping (ORM) framework that simplifies database interactions by providing a high-level object-oriented approach to data access.
    
    
19. How do you handle Cross-Site Scripting (XSS) attacks in ASP.NET?
    Answer: You can prevent XSS attacks by encoding user input, validating input, and using security libraries like the AntiXSS library.
    
    
20. Explain the difference between ViewState and Session state in ASP.NET.
    Answer: ViewState stores page-specific data, while Session state stores user-specific data accessible across multiple pages during a user’s session.
    
    
21. What is the role of the Application_Start and Application_End events in Global.asax?
    Answer: Application_Start is triggered when an application starts, and Application_End is triggered when an application shuts down. These events are used for application-level initialization and cleanup.
    
    
22. How do you implement a custom authentication provider in ASP.NET?
    Answer: You can create a custom authentication provider by implementing the MembershipProvider or IdentityProvider interfaces and configuring it in the web.config file.
    
    
23. Explain the concept of ADO.NET Entity Framework.
    Answer: ADO.NET Entity Framework is an ORM framework that simplifies database access by allowing developers to work with data in an object-oriented way, abstracting the underlying database.
    
    
24. What is AJAX Control Toolkit in ASP.NET, and how is it used?
    Answer: The AJAX Control Toolkit is a collection of ASP.NET server controls and client components that enable you to build rich, interactive web applications using AJAX.
    
    
25. How do you use URL routing in ASP.NET?
    Answer: URL routing allows you to define friendly and more accessible URLs for your application. You can configure routing rules in the Global.asax file.
    
    
26. Explain the purpose of Master Pages in ASP.NET.
    Answer: Master Pages provide a consistent layout and structure for web pages by allowing you to define common elements such as headers, footers, and navigation in a central template.
    
    
27. What is the role of the Web API in ASP.NET?
    Answer: ASP.NET Web API is a framework for building HTTP services that can be consumed by clients, such as web applications and mobile apps, using standard HTTP methods.
    
    
28. How do you implement data validation in ASP.NET?
    Answer: You can use ASP.NET validation controls, attributes, and custom validation logic to validate user input on the client and server side.
    
    
29. What are Bundling and Minification in ASP.NET, and why are they important?
    Answer: Bundling combines multiple CSS or JavaScript files into a single file, and minification reduces their size. This improves page load times by reducing the number of requests and the amount of data transferred.
    
    
30. How do you optimize performance in ASP.NET applications?
    Answer: Performance optimization techniques include caching, minimizing database queries, using efficient algorithms, and reducing unnecessary server round-trips.

These interview questions cover various aspects of ASP.NET development and can help you assess a candidate’s proficiency in this technology.