600+ DOT NET Developer Interview Questions and Answers

Program to print decreasing number of asterisks in each line

• Create a loop to iterate from n to 1

• In each iteration, print the corresponding number of asterisks

• Use a nested loop to print the asterisks in each line

Automated jobs can be created using scheduling tools or by writing custom code to run at specific intervals.

• Use scheduling tools like Windows Task Scheduler or Cron to run jobs at specific intervals

• Write custom code using libraries like Quartz.NET or Hangfire to schedule and run jobs

• Jobs can perform tasks like data backups, sending emails, or running reports

Use LINQ to fetch data from the 'students' table in ascending order of 'studentid'.

• Use LINQ query syntax or method syntax to retrieve data from the 'students' table.

• Order the data by 'studentid' in ascending order using the 'OrderBy' or 'OrderByDescending' method.

• Ensure that the LINQ query is executed against the database to fetch the data.

SQL queries for deleting and updating records based on specific conditions

• For deleting records based on specific conditions: DELETE FROM table_name WHERE condition;

• For updating records based on specific conditions: UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition;

Use SQL query to find the second highest salary employee names in Employee table.

• Use ORDER BY clause to sort the salaries in descending order.

• Use LIMIT 1 OFFSET 1 to get the second highest salary.

• Join the Employee table with itself to get the employee names corresponding to the second highest salary.

The expression (a+b)² can be simplified using the binomial theorem to a² + 2ab + b².

• Use the formula (x+y)² = x² + 2xy + y².

• For (a+b)², set x = a and y = b.

• Result: (a+b)² = a² + 2ab + b².

• Example: If a=2 and b=3, then (2+3)² = 25, which equals 2² + 2*2*3 + 3².

Application pool is a group of one or more worker processes, IIS is a web server, hosting app in dev env involves setting up IIS, abstraction focuses on hiding implementation details, encapsulation bundles data and methods together, optimizing database involves indexing and query optimization, check for application crashes in event logs or monitoring tools.

• Application pool is a group of one or more worker processes that share the same configuration and application boundaries....read more

VB.Net is a programming language while MVC is a design pattern for organizing code in web applications.

• VB.Net is a programming language used for developing applications, while MVC is a design pattern used for organizing code in web applications.

• VB.Net is a part of the .NET framework, whereas MVC is a design pattern that separates an application into three main components: Model, View, and Controller.

• VB.Net can be used with or without the MVC pattern, depending on the project ...read more

Configuration settings can be stored in various places such as appsettings.json, environment variables, database, or Azure Key Vault.

• appsettings.json file in ASP.NET Core projects

• Environment variables for sensitive data

• Database for dynamic configuration

• Azure Key Vault for secure storage

I use Ngrx for state management in my current project by defining actions, reducers, effects, and selectors.

• Define actions to describe user events or interactions

• Create reducers to specify how state should change in response to actions

• Implement effects to manage side effects like API calls

• Use selectors to retrieve specific pieces of state for components

Yes, a program can be written to convert 'aabbccaaa' to '2a2b2c3a'.

• Create a function that iterates through the input string and counts the consecutive characters.

• Store the count and character in a new string as needed.

• Return the final output string.

Design patterns in Dot net are reusable solutions to common problems in software design. To handle multiple requests at the same time, we can use asynchronous programming and multithreading.

• Design patterns in Dot net include Singleton, Factory, Observer, and more.

• To handle multiple requests at the same time, we can use asynchronous programming with async/await keywords.

• Another approach is to use multithreading to process multiple requests concurrently.

• Using Task Parallel Libr...read more

Singleton pattern ensures a class has only one instance and provides a global point of access to it.

• Characteristics include private constructor, static instance variable, static method to access instance, lazy initialization, and thread safety.

• Example: public class Singleton { private static Singleton instance; private Singleton() {} public static Singleton getInstance() { if (instance == null) { instance = new Singleton(); } return instance; }}

The function of an object is to store data and behavior related to a specific entity in a program.

• Objects store data in the form of properties

• Objects can have methods which define behavior

• Objects can be used to model real-world entities like cars, employees, etc.

• Objects can be instantiated from classes or created dynamically

Yes, a table can have multiple primary keys.

• A table can have a composite primary key, which consists of multiple columns.

• Each column in the composite primary key contributes to uniquely identifying each row.

• Example: CREATE TABLE Employee (emp_id INT, dept_id INT, PRIMARY KEY (emp_id, dept_id));

Unique, Primary Key, Clustered, and Non-Clustered Indices are all used in database management to enforce data integrity and improve query performance.

• Unique constraint ensures that all values in a column are unique, but allows NULL values.

• Primary Key constraint ensures that all values in a column are unique and not NULL. Each table can have only one Primary Key.

• Clustered Index physically reorders the way records in the table are stored. Each table can have only one Clustered ...read more

Server side session management involves storing user data on the server to maintain state. Types include in-process, out-of-process, and database.

• In-process session state: Data stored in memory on the same server as the application.

• Out-of-process session state: Data stored in a separate server or service, such as a state server or Redis cache.

• Database session state: Data stored in a database, such as SQL Server or MySQL.

• Examples: ASP.NET session state, PHP session management,...read more

Yes, a class can inherit from both an interface and an abstract class, with the correct order being abstract class first, then interface.

• A class can inherit from one abstract class and multiple interfaces in C#.

• The syntax for inheritance is: 'class ClassName : AbstractClass, IInterface'.

• Example: 'class MyClass : MyAbstractClass, IMyInterface'.

• Abstract classes can provide default implementations, while interfaces define contracts.

• C# allows multiple interface inheritance but on...read more

ROW_NUMBER() and PARTITION BY are used in SQL to assign a unique row number to each row within a partition.

• Use ROW_NUMBER() function along with PARTITION BY clause to assign a unique row number to each row within a partition.

• To find duplicates in a table, you can use a combination of ROW_NUMBER() and PARTITION BY to identify rows with row numbers greater than 1.

• Example: SELECT * FROM (SELECT *, ROW_NUMBER() OVER(PARTITION BY column_name ORDER BY column_name) AS row_num FROM t...read more

The .NET Framework is a Windows-only framework, while .NET Core is cross-platform and open-source.

• The .NET Framework is a Windows-only framework, while .NET Core is cross-platform and open-source.

• .NET Framework is a mature framework with a large number of libraries, while .NET Core is a lightweight framework with fewer libraries.

• .NET Framework requires Windows to run, while .NET Core can run on Windows, Linux, and macOS.

• The .NET Framework is not open-source, while .NET Core i...read more

Union combines and removes duplicates, Union All combines all rows including duplicates.

• Union merges the results of two or more SELECT statements into a single result set.

• Union All returns all rows from all SELECT statements, including duplicates.

• Union requires the same number of columns in all SELECT statements, while Union All does not.

• Union sorts the result set and removes duplicates, while Union All does not.

• Union is slower than Union All because it performs additional pr...read more

Authorization and authentication in web API can be set using various methods like JWT, OAuth, and Identity Framework.

• Use JWT (JSON Web Tokens) for token-based authentication

• Implement OAuth for secure authorization and authentication

• Utilize Identity Framework for managing user authentication and authorization

• Set up roles and policies to control access to resources

IEnumerable is used for in-memory collection operations, while IQueryable is used for database query operations.

• IEnumerable is used for querying data from in-memory collections like arrays, lists, etc.

• IQueryable is used for querying data from a database using LINQ to SQL or Entity Framework.

• IEnumerable executes the query in-memory, while IQueryable executes the query on the database server.

• IEnumerable is suitable for LINQ to Objects, while IQueryable is suitable for LINQ to E...read more

The new row will start from 1 after truncating a table.

• Truncating a table removes all rows from the table, resetting the row count to 1.

• The next row inserted after truncation will have an ID of 1.

• Truncating a table does not reset the auto-increment value of the primary key column.

I have worked on various projects including web applications, desktop applications, and mobile applications.

• Developed a web application using ASP.NET MVC and Entity Framework

• Created a desktop application using WPF and MVVM pattern

• Built a mobile application using Xamarin.Forms

• Used garbage collector to manage memory in all projects

• Handled different types of data such as text, images, and videos

IEnumerable, IQueryable, and List are collections in .NET with different use cases and performance characteristics.

• IEnumerable: Represents a forward-only cursor for iterating over a collection. Example: IEnumerable<int> numbers = new List<int> { 1, 2, 3 };

• IQueryable: Designed for querying data from a data source, allowing for LINQ queries to be translated to SQL. Example: IQueryable<Customer> customers = dbContext.Customers;

• List: A concrete collection that provides methods fo...read more

Filters, routing, and caching are important concepts in MVC. Authorization in API can be achieved using authentication mechanisms.

• Filters in MVC are used to perform logic before or after an action method is executed.

• Routing in MVC is used to map URLs to controller actions.

• Caching in MVC is used to store data temporarily to improve performance.

• Authorization in API can be achieved using authentication mechanisms like JWT tokens or OAuth.

• Example: Using [Authorize] attribute in A...read more