50+ ASP.NET Developer Interview Questions and Answers

Explanation of OOP concepts like constructor, delegates, inheritance, and abstract class.

• Constructor is a special method that is called when an object is created.

• Delegates are type-safe function pointers used to reference methods.

• Inheritance is a mechanism that allows a class to inherit properties and methods from another class.

• Abstract class is a class that cannot be instantiated and is used as a base class for other classes.

Primary key uniquely identifies each record in a table, while unique key ensures that all values in a column are different.

• Primary key does not allow NULL values, while unique key allows one NULL value.

• A table can have only one primary key, but multiple unique keys.

• Primary key is automatically indexed, while unique key is not.

• Example: Primary key for a table of students could be student_id, while unique key could be email_id.

MVC is a software architecture pattern that separates an application into three main components: Model, View, and Controller. ActionResults are methods that return data to the client.

• Model: represents the data and business logic of the application

• View: represents the user interface of the application

• Controller: handles user input and updates the model and view accordingly

• ActionResults: methods that return data to the client, such as a view or JSON data

• Examples of ActionResult...read more

MVC application flow involves the request being handled by the controller, which interacts with the model to retrieve data and then passes it to the view for rendering.

• 1. Request is received by the controller

• 2. Controller interacts with the model to retrieve data

• 3. Data is passed to the view for rendering

• 4. View generates the HTML response to be sent back to the client

StateManagement in ASP.NET refers to the techniques used to preserve data between multiple requests from the same user.

• StateManagement is important for maintaining the state of controls on a web page across postbacks.

• There are different ways of managing state in ASP.NET such as ViewState, Session, Cookies, and Application state.

• ViewState is used to store page-specific information that is preserved across postbacks.

• Session state is used to store user-specific information that ...read more

Abstraction is the concept of hiding complex implementation details and showing only the necessary information. Interface is a contract that defines the methods that a class must implement.

• Abstraction allows us to focus on what an object does instead of how it does it.

• Interface defines a set of methods that a class must implement, but it does not provide the implementation details.

• Abstraction can be achieved through abstract classes and interfaces in object-oriented programmi...read more

Use the SELECT TOP statement in SQL to retrieve the top 5 records from a table.

• Use the SELECT statement to specify the columns you want to retrieve.

• Use the TOP keyword followed by the number of records you want to retrieve.

• Specify the table name in the FROM clause.

• Add any necessary conditions in the WHERE clause.

• Order the results if needed using the ORDER BY clause.

I have used various tools including Visual Studio, Git, JIRA, and SQL Server Management Studio.

• Visual Studio for coding and debugging

• Git for version control

• JIRA for project management

• SQL Server Management Studio for database management

Abstraction focuses on the outside view of an object while encapsulation deals with the internal workings of an object.

• Abstraction is the process of hiding complex implementation details and showing only necessary information to the user.

• Encapsulation is the process of wrapping data and methods into a single unit (class) and restricting access to the data from outside the class.

• Abstraction is achieved through interfaces and abstract classes.

• Encapsulation is achieved through a...read more

Session data in ASP.NET is stored either in-process, out-of-process, or in a SQL Server database.

• In-process storage stores session data in memory on the web server.

• Out-of-process storage stores session data in a separate process, such as State Server or SQL Server.

• SQL Server database storage stores session data in a SQL Server database.

• Session data can be configured in web.config file using element.

Label control is used to display text while Literal control is used to display HTML content.

• Label control is a lightweight control that displays text on a web page.

• Literal control is used to display HTML content on a web page.

• Label control is rendered as a span element while Literal control is rendered as the HTML content it contains.

• Label control does not allow HTML tags while Literal control allows HTML tags.

• Label control is faster than Literal control.

Functions return a value while stored procedures do not.

• Functions can be used in SQL statements while stored procedures cannot.

• Functions can be called from within stored procedures.

• Functions can be used in views while stored procedures cannot.

• Functions can have input parameters while stored procedures can have both input and output parameters.

Abstract classes can have implementation while interfaces cannot. Classes can implement multiple interfaces but only inherit from one abstract class.

• Abstract classes can have constructors while interfaces cannot

• Interfaces can only have method signatures while abstract classes can have both method signatures and implementation

• Abstract classes can have access modifiers while interfaces cannot

• Classes can implement multiple interfaces but only inherit from one abstract class

Page life cycle in ASP.NET is the sequence of events that occur during the processing of a web page.

• Page life cycle consists of various stages like initialization, loading, postback, rendering, and unloading.

• During initialization, the page and controls are created and their properties are set.

• During loading, the page retrieves and processes the user input.

• During postback, the page handles the events raised by the user.

• During rendering, the page generates the HTML markup to be...read more

A class is a blueprint or template for creating objects, while an object is an instance of a class.

• A class defines the properties and methods that an object will have.

• An object is created from a class using the 'new' keyword.

• Multiple objects can be created from a single class.

• Classes can inherit properties and methods from other classes.

• Objects can have unique values for their properties, while classes define the structure of those properties.

I have the necessary skills, experience, and passion to excel in this role.

• I have extensive experience in ASP.NET development.

• I am a quick learner and can adapt to new technologies easily.

• I am a team player and can work collaboratively with others.

• I am passionate about coding and always strive to improve my skills.

• I have a strong work ethic and am committed to delivering high-quality work.

Running projects in a company requires selecting the appropriate technology for the project.

• Consider the project requirements and constraints

• Evaluate available technologies and their suitability

• Choose the technology that best fits the project needs

• Ensure the technology is compatible with existing systems

• Train team members on the selected technology

Web technologies refer to the tools and techniques used to create, manage, and deliver web-based applications and services.

• Web technologies include programming languages like HTML, CSS, JavaScript, and server-side languages like PHP, ASP.NET, and Java.

• Web technologies also include frameworks and libraries like React, Angular, and jQuery.

• Web technologies are used to create websites, web applications, and web services that can be accessed through the internet.

• Web technologies a...read more

SQL is a programming language used for managing and manipulating databases. Joins are used to combine rows from two or more tables based on a related column between them.

• SQL stands for Structured Query Language and is used to interact with databases.

• Joins are used to combine data from multiple tables based on a related column.

• Common types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2...read more

ASP.NET is a web application framework developed by Microsoft.

• It allows developers to build dynamic web applications and services.

• It supports multiple programming languages such as C#, VB.NET, and F#.

• It provides a rich set of libraries and tools for building web applications.

• It includes features such as authentication, caching, and session management.

• It can be used to build web applications for desktop and mobile devices.

MVC is a software architecture pattern that separates an application into three interconnected components: Model, View, and Controller.

• Model represents the data and business logic of the application

• View is responsible for rendering the user interface

• Controller handles user input and updates the model and view accordingly

Interfaces define only method signatures while abstract classes can have method implementations.

• Interfaces cannot have method implementations, abstract classes can.

• A class can implement multiple interfaces but can inherit only one abstract class.

• Interfaces are used for defining contracts, abstract classes are used for code reusability.

• Interfaces are more flexible as they allow multiple inheritance through interfaces.

• Abstract classes can have constructors, interfaces cannot.

Runtime polymorphism is the ability of a method to be dynamically bound at runtime based on the type of the object.

• It allows a subclass to provide its own implementation of a method that is already defined in its parent class.

• It is achieved through method overriding.

• The decision of which method to execute is determined by the actual type of the object at runtime.

• It enables code reusability and flexibility in object-oriented programming.

• Example: Animal class has a method calle...read more

View state is used to persist the state of a web form across postbacks in ASP.NET.

• View state can be enabled or disabled at the page level or control level.

• Different types of view state include enabled, disabled, and encrypted.

• View state can be used to store values of controls on a web form between postbacks.

Enum is a type that represents a set of named constants while constant is a fixed value that does not change.

• Enum can have multiple named constants with unique values, while constant is a single fixed value.

• Enums are used when a variable can only have a few possible values, while constants are used for values that do not change.

• Enums can be used in switch statements, while constants cannot.

• Example: enum Colors { Red, Green, Blue } vs const int MaxValue = 100;

The four pillars of OOP are encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundling data and methods that operate on the data into a single unit (class).

• Inheritance: Allowing a class to inherit properties and behavior from another class.

• Polymorphism: The ability for objects of different classes to respond to the same method call.

• Abstraction: Hiding the complex implementation details and showing only the necessary features of an object.

Sealed class is used to prevent inheritance and ensure that the class cannot be extended.

• Prevents inheritance, ensuring that the class cannot be extended

• Helps in maintaining code integrity and security

• Used when a class is not intended to be inherited or overridden

RESTful APIs are a type of web service that follows the principles of REST (Representational State Transfer) architecture.

• RESTful APIs use standard HTTP methods like GET, POST, PUT, DELETE to perform CRUD operations on resources.

• They are stateless, meaning each request from a client to the server must contain all the information necessary to understand the request.

• RESTful APIs typically return data in JSON or XML format.

• They are designed to be scalable and easily maintainable...read more

Stored procedures are precompiled SQL queries stored in a database for reuse.

• Stored procedures are used to improve performance by reducing the need to send multiple queries to the database server.

• They can be parameterized to accept input values and return results.

• Stored procedures can contain logic and business rules, making them reusable and secure.

• Examples include procedures for inserting, updating, and deleting data in a database.

Dependency injection is a design pattern in which a class receives its dependencies from external sources rather than creating them itself.

• Allows for better code reusability and testability

• Promotes loose coupling between classes

• Commonly used in ASP.NET Core for managing services and components

MVC models are a design pattern for web applications. Action Listeners are used to handle user input.

• MVC stands for Model-View-Controller

• Model represents the data and business logic

• View is the user interface

• Controller handles user input and updates the model and view

• Action Listeners are used in GUI programming to handle user input events

• For example, a button click can trigger an Action Listener to perform a specific action

OOPs concepts in C# include inheritance, encapsulation, polymorphism, and abstraction.

• Inheritance allows a class to inherit properties and methods from another class.

• Encapsulation is the practice of hiding implementation details and exposing only necessary information.

• Polymorphism allows objects of different types to be treated as if they are the same type.

• Abstraction is the process of hiding complex implementation details and providing a simplified interface for the user.

• Exa...read more

Output cache stores the output of a page or user control so that it can be quickly retrieved for subsequent requests.

• Output cache is used to improve the performance of web applications.

• It reduces the number of requests made to the server by storing the output of a page or user control.

• Output cache can be set at the page level or at the application level.

• It can be configured to expire after a certain amount of time or when certain conditions are met.

• Output cache can be used to...read more

The 4 pillars of object-oriented programming are encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Inheritance: Allowing a class to inherit properties and behavior from another class.

• Polymorphism: The ability for objects of different classes to respond to the same message.

• Abstraction: Hiding the complex implementation details and showing only the necessary features.

Inheritance is a mechanism in OOP where a new class is derived from an existing class.

• Inheritance allows for code reuse and promotes code organization.

• The derived class inherits all the properties and methods of the base class.

• The derived class can also override or extend the functionality of the base class.

• There are different types of inheritance such as single, multiple, and hierarchical inheritance.

• Example: A Car class can be derived from a Vehicle class, inheriting its pr...read more

View state is a hidden field on an ASP.NET web page that stores state information.

• View state is used to persist page and control state across postbacks.

• It is stored as a hidden field on the page and is encrypted by default.

• View state can be disabled to improve performance, but it may lead to loss of state information.

Transient objects are created each time they are requested, while scoped objects are created once per request.

• Transient objects are created every time they are requested, leading to potentially higher memory usage.

• Scoped objects are created once per request and are shared within the scope of that request.

• Example: Transient objects are typically used for lightweight services, while scoped objects are used for services that need to maintain state within a request.

Stored procedure is a precompiled SQL query that is stored in the database for reuse.

• Stored procedures improve performance by reducing network traffic and increasing security.

• They can accept parameters and return results like a regular query.

• Stored procedures can be called from application code to execute complex logic on the database side.

• Example: CREATE PROCEDURE GetCustomers AS SELECT * FROM Customers;

Startup file is a configuration file in ASP.NET that specifies settings and behavior for the application.

• Startup file is typically named 'Startup.cs' in ASP.NET Core projects.

• It contains configuration for services, middleware, and the request processing pipeline.

• The 'ConfigureServices' method is used to add services to the dependency injection container.

• The 'Configure' method is used to configure the HTTP request pipeline.

• Startup file is responsible for setting up the applica...read more

Polymorphism is the ability of an object to take on many forms. It allows objects of different classes to be treated as the same type.

• Polymorphism is a fundamental concept in object-oriented programming.

• It allows a single interface to be used for different types of objects.

• Polymorphism is achieved through method overriding and method overloading.

• Example: A base class Animal can have derived classes like Dog, Cat, and Bird, all implementing their own unique behavior while stil...read more

ASP.NET MVC is a web application framework developed by Microsoft that implements the model-view-controller pattern.

• ASP.NET MVC separates the application into three main components: Model, View, and Controller.

• Model represents the application's data and business logic.

• View represents the user interface.

• Controller handles user input and updates the model and view accordingly.

• ASP.NET MVC provides better control over HTML, CSS, and JavaScript compared to Web Forms.

• It supports te...read more

OOP stands for Object-Oriented Programming, a programming paradigm based on the concept of objects.

• OOP focuses on creating objects that contain both data and methods to manipulate that data.

• Encapsulation, inheritance, and polymorphism are key principles of OOP.

• Examples of OOP languages include Java, C++, and C#.

API lifetimes refer to the duration for which an API is available and supported.

• API lifetimes can vary depending on the service provider or platform.

• Some APIs may have a limited lifetime and be deprecated after a certain period.

• Developers should be aware of API lifetimes to plan for potential changes or updates.

• Regularly check for updates or announcements regarding API lifetimes to stay informed.

SOLID principles are a set of five design principles that help developers create more maintainable and scalable software.

• S - Single Responsibility Principle: A class should have only one reason to change.

• O - Open/Closed Principle: Software entities should be open for extension but closed for modification.

• L - Liskov Substitution Principle: Objects of a superclass should be replaceable with objects of its subclasses without affecting the program's correctness.

• I - Interface Segr...read more

MVC life cycle is the sequence of events that occur during the processing of a web request in ASP.NET MVC.

• 1. Routing: Determines which controller and action method to call based on the URL.

• 2. Controller: Executes the action method and returns a ViewResult or other types of results.

• 3. View: Renders the HTML output to be sent back to the client.

• 4. Model Binding: Maps the data from the request to the action method parameters.

• 5. Action Filters: Allow you to run code before or aft...read more

I have worked on ASP.NET, C#, SQL Server, JavaScript, HTML, CSS

• ASP.NET

• C#

• SQL Server

• JavaScript

• HTML

• CSS

Object-oriented programming (OOP) is a programming paradigm based on the concept of objects, which can contain data and code.

• OOP focuses on creating objects that interact with each other to solve problems

• Encapsulation: bundling data and methods that operate on the data into a single unit (object)

• Inheritance: allows a class to inherit properties and behavior from another class

• Polymorphism: the ability for objects to be treated as instances of their parent class or their own cl...read more