Q1. What is ASP.NET?

ASP.NET is a web application framework developed by Microsoft used for building dynamic web pages and web applications. It is part of the .NET platform.

Q2. What are the different types of ASP.NET applications?

There are three types of ASP.NET applications:
1. Web Forms: It uses server-side controls and user controls to create web pages.
2. MVC (Model-View-Controller): It follows a design pattern for separation of concerns and allows for more control over the HTML markup.
3. Web API: It is used to build RESTful services that can be consumed by various clients.

Q3. What is the difference between ASP.NET Web Forms and ASP.NET MVC?

ASP.NET Web Forms uses a page-based approach, where the web application is built as a series of forms. ASP.NET MVC, on the other hand, follows the Model-View-Controller pattern, separating the concerns of data, presentation, and user interaction.

Q4. Explain the event life cycle in ASP.NET Web Forms.

The event life cycle in ASP.NET Web Forms consists of the following stages:
1. Page Initialization
2. Page Load
3. Validation
4. Postback Event Handling
5. Rendering
6. Unloading

Q5. What is ViewState and how is it used?

ViewState is used to persist state across Postbacks in ASP.NET Web Forms. It is a hidden field that stores values for controls on a page. ViewState is enabled by default, but it can be turned off for specific controls or the entire page.

Q6. What is the difference between Server.Transfer and Response.Redirect?

Server.Transfer transfers control from one page to another without making a round-trip to the client’s browser. Response.Redirect, on the other hand, sends a response to the browser with a new URL, causing the browser to make a new request.

Q7. What are the different caching options available in ASP.NET?

ASP.NET provides several caching options:
1. Output Caching: Caches the output of a page or user control for a specified time.
2. Fragment Caching: Caches a portion of a page or user control for a specified time.
3. Data Caching: Caches the results of a data query for a specified time.
4. Application Caching: Caches data shared by multiple users.

Q8. Explain the difference between Session state and Application state.

Session state is used to store user-specific data across multiple requests. It is specific to each user and is maintained using a unique session ID. Application state, on the other hand, is shared among all users of an application and is maintained by the server.

Q9. What are ASP.NET Validators?

ASP.NET Validators are used to validate user input on web forms. There are various types of validators such as RequiredFieldValidator, RangeValidator, RegularExpressionValidator, etc.

Q10. What is the Global.asax file used for?

The Global.asax file contains application-level event handlers and configuration settings. It is used to handle application-level events like Application_Start, Session_Start, Application_Error, etc.

Q11. How can you handle errors in ASP.NET?

Errors in ASP.NET can be handled using various methods, including:
1. Using try-catch blocks
2. Using custom error pages configured in the web.config file
3. Using the Application_Error event in Global.asax

Q12. What is the difference between Server-side and Client-side scripting?

Server-side scripting refers to scripts executed on the server before being sent to the client’s browser. It allows for dynamic content generation and database operations. Client-side scripting, on the other hand, refers to scripts executed in the client’s browser using JavaScript. It enables interaction with the user interface.

Q13. What is the use of the using statement in ASP.NET?

The using statement in ASP.NET is used to automatically dispose of resources such as database connections, file handles, etc. It ensures that resources are released even if an exception occurs.

Q14. What is the difference between GET and POST methods in ASP.NET?

GET method sends data to the server as part of the URL, visible to the user. It is suitable for retrieving data or performing read-only operations. POST method sends data in the body of the HTTP request, not visible to the user. It is suitable for sending large amounts of data or performing write operations.

Q15. What is the ViewStateMode property used for?

The ViewStateMode property is used to control how ViewState is rendered for individual controls. It can have values of Enabled, Disabled, or Inherit.

Q16. What is the difference between User Controls and Custom Controls in ASP.NET?

User Controls are built using a combination of HTML and server-side code and have a file extension of .ascx. They are easy to create and modify. Custom controls, on the other hand, are compiled into a DLL and have a file extension of .dll. They offer more flexibility and reusability but require more effort to create and modify.

Q17. How can you handle authentication and authorization in ASP.NET?

Authentication and authorization can be handled in ASP.NET using the ASP.NET Membership and Role Management framework. It provides user authentication, user registration, password recovery, and role-based access control.

Q18. What is the Globalization and Localization in ASP.NET?

Globalization refers to designing and developing applications that can be localized for different cultures and languages. Localization refers to adapting an application to a specific culture and language by providing localized resources such as date formats, currency symbols, etc.

Q19. What are the different types of caching available in ASP.NET?

The different types of caching available in ASP.NET are:
1. Output Caching
2. Fragment Caching
3. Data Caching
4. Application Caching
5. SQL Caching

Q20. What is the purpose of the Web.config file?

The Web.config file is used to define configuration settings for an ASP.NET application. It includes settings for application-level parameters, connection strings, session state, authentication, and more.

1. What is the difference between ASP.NET Web Forms and ASP.NET MVC?
ASP.NET Web Forms is based on event-driven programming model and uses controls and view state, while ASP.NET MVC is based on the Model-View-Controller pattern where the controller handles the user input, the model manages data, and the view is responsible for UI rendering.

2. Explain the concept of ASP.NET routing.
ASP.NET routing is a mechanism that maps URLs to specific handlers or controllers. It enables creating user-friendly URLs without the need for physical files. Routing allows for cleaner and more expressive URLs.

3. What is MVC and how does it relate to ASP.NET?
MVC stands for Model-View-Controller and is a design pattern that separates the application into three interconnected components. In the context of ASP.NET, ASP.NET MVC is a web application framework that implements the MVC pattern for building scalable and maintainable web applications.

4. What are the advantages of using ASP.NET Web API over WCF?
ASP.NET Web API is a lightweight framework for building HTTP services and is ideal for creating RESTful APIs. It has a simpler programming model, supports multiple data formats, and is based on standard HTTP verbs and status codes. In comparison, WCF is a more comprehensive framework that supports various protocols and message patterns.

5. How can you implement cross-site scripting (XSS) prevention in ASP.NET?
To prevent cross-site scripting attacks, you can use ASP.NET’s built-in security features like request validation and output encoding. Additionally, you can use anti-XSS libraries and frameworks to sanitize user input and prevent malicious script execution.

6. What are the different types of caching in ASP.NET?
ASP.NET provides several types of caching mechanisms, including output caching, data caching, and fragment caching. Output caching allows you to cache the entire rendered output of a page or user control. Data caching allows you to cache data retrieved from a data source, improving performance. Fragment caching allows you to cache specific portions of a page.

7. How can you implement authentication and authorization in ASP.NET?
ASP.NET provides various authentication and authorization mechanisms, such as Forms Authentication, Windows Authentication, and Role-Based Authorization. Forms Authentication allows users to log in using credentials stored in a database or other data source, while Windows Authentication uses Windows accounts for authentication.

8. What is the difference between ViewBag and ViewData in ASP.NET MVC?
ViewData is a dictionary-like object that allows you to pass data from a controller to a view, while ViewBag is a dynamic wrapper around the ViewData object. ViewBag provides a more concise syntax for accessing data in the view.

9. What is dependency injection and how can it be achieved in ASP.NET?
Dependency Injection is a design pattern that allows you to inject dependencies into a class rather than creating them directly. In ASP.NET, you can achieve dependency injection using frameworks like Ninject, Unity, or the built-in DependencyResolver.

10. What are the different types of filters in ASP.NET MVC?
ASP.NET MVC provides various types of filters, including Authorization filters, Action filters, Result filters, and Exception filters. Authorization filters allow you to authenticate and authorize requests. Action filters allow you to perform actions before or after the execution of an action method. Result filters operate on the result of an action method, and Exception filters handle exceptions thrown during the execution.

11. What is Entity Framework and how does it relate to ASP.NET?
Entity Framework is an ORM (Object Relational Mapping) framework that simplifies database interactions by mapping database tables to .NET objects. It provides a higher-level abstraction for working with databases and enables rapid development of data-driven applications in ASP.NET.

12. What is an async/await in ASP.NET?
Async and await are keywords introduced in C# 5.0 that enable asynchronous programming in ASP.NET. The async keyword allows a method to be marked as asynchronous, and the await keyword is used to wait for an asynchronous operation to complete without blocking the thread.

13. How can you optimize the performance of an ASP.NET application?
There are several ways to optimize the performance of an ASP.NET application, such as:
– Enabling caching for frequently accessed data
– Minifying and bundling CSS and JavaScript files
– Implementing output caching for pages or user controls
– Using database optimization techniques like indexing and query optimization
– Enabling compression for HTTP responses

14. What are the different session state modes in ASP.NET?
ASP.NET offers three session state modes: InProc (stores session data in memory on the web server), StateServer (stores session data in a separate process called the ASP.NET state service), and SQLServer (stores session data in a SQL Server database).

15. How can you handle errors and exceptions in ASP.NET?
In ASP.NET, you can handle errors and exceptions using try-catch blocks, the Application_Error event in Global.asax, custom error pages, and the Elmah library for logging and managing errors.

16. How can you enable routing in ASP.NET Web Forms?
While ASP.NET Web Forms primarily relies on the control-based event-driven model, you can enable routing in Web Forms by using the URL Routing module and configuring routes in the RouteConfig file.

17. What is the purpose of the Global.asax file in ASP.NET?
The Global.asax file is an ASP.NET file that acts as the global event handler for an application. It allows you to handle application-level events, such as Application_Start, Application_End, and Session_Start.

18. What is the purpose of the App_Code folder in ASP.NET?
The App_Code folder is a special folder in an ASP.NET application that is used for storing source code files that are dynamically compiled at runtime. It is commonly used for placing shared classes and utility functions.

19. What is the use of the ViewState in ASP.NET Web Forms?
The ViewState is a hidden field in an ASP.NET Web Form that is used to store the state of server-side controls across postbacks. It allows for retaining control values and property settings between page requests.

20. How can you handle concurrency and data conflicts in ASP.NET?
In ASP.NET, you can handle concurrency and data conflicts by implementing concurrency control mechanisms, such as optimistic concurrency with timestamp or row versioning. Furthermore, you can use transaction isolation levels to manage data consistency and prevent data conflicts.