20+ .NET Application Developer Interview Questions and Answers

Sealed classes cannot be inherited from. They are used to prevent inheritance and ensure class integrity.

• Sealed classes are declared using the 'sealed' keyword in C#.

• They are used to prevent other classes from inheriting from them.

• Sealed classes can inherit from other classes, but they cannot be inherited from.

Cursors in SQL are used to iterate through a result set, triggers are not always required but can be useful for enforcing business rules.

• Cursors in SQL are used to fetch and process individual rows from a result set.

• Triggers in SQL are used to automatically perform actions when certain events occur in a database.

• Triggers can be useful for enforcing data integrity constraints or auditing changes to data.

• Syntax of a trigger: CREATE TRIGGER trigger_name ON table_name FOR INSERT,...read more

Abstract class is a class that cannot be instantiated and may contain abstract methods. Interface is a contract that defines methods that a class must implement.

• Abstract class can have both abstract and non-abstract methods, while interface can only have abstract methods.

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

• Abstract classes are used when you want to provide a default implementation for some methods, while interfaces are used to def...read more

GC stands for Garbage Collection. It is a process of automatically reclaiming memory occupied by objects that are no longer in use.

• GC is a part of the .NET runtime that manages memory by automatically freeing up memory occupied by objects that are no longer needed.

• We can suggest the GC to run by calling the GC.Collect() method, but it is not recommended to force GC as it can have performance implications.

• Forcing GC to run can be done by calling GC.Collect() method with option...read more

Encapsulation is the concept of bundling data and methods that operate on the data into a single unit. Abstraction is the concept of hiding the implementation details and showing only the necessary features of an object.

• Encapsulation helps in data hiding and prevents direct access to data from outside the class.

• Abstraction helps in reducing complexity by hiding unnecessary details and showing only essential features.

• Encapsulation is achieved by using access modifiers like pri...read more

SOLID is a set of five design principles in object-oriented programming. One of them is the Single Responsibility Principle (SRP).

• SRP states that a class should have only one reason to change, meaning it should only have one job or responsibility.

• For example, a class that handles both user authentication and database operations violates SRP. It should be split into two separate classes.

• SRP helps in making code more maintainable, testable, and easier to understand.

Routing is the process of directing network traffic to its destination. Conventional Routing is a method of defining routes based on conventions.

• Routing is the process of determining the path that network packets should take from the source to the destination.

• Conventional Routing involves defining routes based on conventions or predefined rules.

• In web development, routing refers to mapping URLs to specific controllers and actions in an application.

• Conventional Routing in ASP....read more

Error handling in .NET application involves using try-catch blocks to handle exceptions and ensure graceful error recovery.

• Use try-catch blocks to catch exceptions and handle them appropriately

• Use specific exception types for different error scenarios

• Implement logging to track errors and troubleshoot issues

• Consider using global exception handling for unhandled exceptions

• Use custom error messages to provide meaningful feedback to users

Code deployment in test environment involves creating a deployment package and deploying it to the test server.

• Create a deployment package containing all necessary files and configurations.

• Deploy the package to the test server using tools like Octopus Deploy or Azure DevOps.

• Test the deployed code in the test environment to ensure it functions as expected.

MVC page cycle is the sequence of events that occur during the lifespan of a MVC page.

• MVC page is requested by the user

• Routing engine determines the appropriate controller and action method

• Controller executes the action method and returns a view

• View is rendered and sent back to the user's browser

Global tables are accessible to all sessions, while temp tables are only accessible to the session that created them.

• Global tables are permanent and stored in the database, while temp tables are temporary and stored in memory or tempdb.

• Global tables can be accessed by multiple users and sessions, while temp tables are local to the session that created them.

• Global tables require explicit creation and dropping, while temp tables are automatically dropped when the session ends o...read more

Regular expression is a sequence of characters that define a search pattern.

• Regular expressions are used for pattern matching in strings

• They can be used for tasks like validation, searching, and replacing text

• Examples: ^[a-zA-Z0-9]+@[a-zA-Z0-9]+\.[a-zA-Z]{2,4}$ is a regex for email validation

ACID properties ensure database transactions are processed reliably.

• ACID stands for Atomicity, Consistency, Isolation, and Durability.

• Atomicity ensures that either all operations in a transaction are completed or none are.

• Consistency ensures that the database remains in a valid state before and after the transaction.

• Isolation ensures that multiple transactions can occur concurrently without affecting each other.

• Durability ensures that once a transaction is committed, it will ...read more

ASP .Net Page Lifecycle is a series of events that occur when a page is requested, processed, and rendered by the server.

• Page Request: Initiated by the user or browser.

• Page Initialization: Page properties are set.

• Page Load: Controls on the page are loaded and data is bound.

• Postback Event Handling: User interactions trigger events.

• Page Rendering: Page is rendered to HTML and sent to the browser.

• Page Unload: Cleanup and finalization tasks.

MasterPage is a feature in ASP.NET that allows for creating a consistent layout for multiple pages.

• MasterPage defines the common structure and interface for all pages in a web application.

• It allows for the separation of content and layout, making it easier to maintain and update.

• MasterPage can contain placeholders for content that can be filled in by individual pages.

• Changes made to the MasterPage will be reflected across all pages that use it.

• Example: Creating a MasterPage w...read more

Lazy loading is a design pattern where data is loaded only when it is needed.

• Lazy loading helps improve performance by loading data on demand

• It is commonly used in ORM frameworks like Entity Framework

• Example: Loading related entities only when accessed in a database query

The var keyword is not used in SQL, it is used in C# to declare implicitly typed variables.

• The var keyword in C# allows you to declare a variable without explicitly specifying the type, the type is inferred by the compiler.

• In SQL, you must explicitly specify the data type when declaring variables or columns.

• Example in C#: var number = 10; // Compiler infers that number is an integer

• Example in SQL: DECLARE @name VARCHAR(50); // Explicitly specifying the data type