Top 30 C# Interview Questions and Answers 2024

C# is a programming language while .NET is a framework that supports multiple languages including C#.

• C# is a programming language developed by Microsoft.

• .NET is a framework developed by Microsoft that supports multiple languages including C#.

• C# is used to write code, while .NET provides libraries and tools for building applications.

• C# code is compiled into Intermediate Language (IL) which runs on the .NET Common Language Runtime (CLR).

C# is a programming language developed by Microsoft for building applications on the .NET framework.

• C# is a modern, object-oriented language with similarities to Java.

• .NET is a software framework developed by Microsoft for building and running applications.

• C# and .NET are commonly used for developing web applications, desktop applications, and mobile apps.

• C# code is compiled into Intermediate Language (IL) which runs on the Common Language Runtime (CLR) in the .NET framework.

Wap in Linq to get a name of user starting with 'tom'

• Use 'Where' method with 'StartsWith' to filter the names

• Use 'Select' method to get only the names

• Use 'ToArray' method to convert the result to an array of strings

Yes, I know both SQL and C#.

• I have experience in writing SQL queries for database management.

• I have worked on C# projects for developing desktop and web applications.

• I am familiar with object-oriented programming concepts and database design principles.

Program in C# demonstrating OOPs concepts

• Use classes and objects to demonstrate encapsulation

• Inheritance can be shown by creating a base class and derived classes

• Polymorphism can be illustrated through method overriding or interfaces

• Abstraction can be implemented by hiding internal details and showing only necessary information

I have completed 5 projects in C# including a web application, a desktop application, and a game.

• Developed a web application using ASP.NET MVC

• Created a desktop application for data management

• Designed a game using Unity and C# scripting

Memory management in C# involves automatic garbage collection and the use of pointers.

• C# uses a garbage collector to automatically manage memory allocation and deallocation.

• Developers can use pointers to directly manipulate memory, but this is not recommended.

• C# also provides tools for managing memory usage, such as the IDisposable interface and the using statement.

Parallel programming in C# allows multiple tasks to be executed simultaneously for improved performance.

• Parallel programming can be achieved using the Task Parallel Library (TPL) in C#.

• TPL provides constructs like Parallel.For and Parallel.ForEach to execute loops in parallel.

• Parallel.Invoke can be used to execute multiple methods in parallel.

• Data parallelism can be achieved using PLINQ (Parallel LINQ) to execute LINQ queries in parallel.

• Parallel programming can improve perfo...read more

C# has various types of operators including arithmetic, comparison, logical, bitwise, and assignment operators.

• Arithmetic operators perform mathematical operations on numeric operands (+, -, *, /, %)

• Comparison operators compare two values and return a boolean result (==, !=, >, <, >=, <=)

• Logical operators perform logical operations on boolean operands (&&, ||, !)

• Bitwise operators perform operations on individual bits of integer operands (&, |, ^, ~, <<, >>)

• Assignment operator...read more

C# is used in legacy systems for maintaining and updating existing software applications.

• C# can be used to extend the functionality of legacy systems by integrating new features and technologies.

• It allows for easier maintenance and updates to existing codebase.

• C# can also be used to modernize legacy systems by migrating them to newer platforms or frameworks.

• Examples include updating a legacy desktop application to a web-based application using C#.

Error handling in c# involves using try-catch blocks to handle exceptions and ensure graceful handling of errors.

• Use try-catch blocks to catch exceptions and handle errors gracefully.

• Use specific exception types to catch specific errors.

• Use finally block to ensure cleanup code is executed regardless of whether an exception is thrown.

• Throw custom exceptions to provide meaningful error messages to users.

• Use logging to track and debug errors in production environments.

C# is a modern, object-oriented programming language developed by Microsoft.

• C# is used to develop Windows desktop applications, games, mobile apps, and web applications.

• It is strongly typed and supports both value and reference types.

• C# uses a syntax similar to Java and C++.

• It includes features such as garbage collection, delegates, and lambda expressions.

• C# is part of the .NET framework and can be used with other .NET languages like VB.NET and F#.

Const keyword is used to declare constants at compile time, while read-only keyword is used to create immutable fields that can only be assigned a value at runtime.

• Const values are determined at compile time and cannot be changed, while read-only values can only be assigned a value once at runtime.

• Const fields are implicitly static, while read-only fields are not.

• Example: const int x = 5; read-only int y = 10;

Sealed class is a class that cannot be inherited. It is used to prevent derivation of a class.

• Sealed classes are declared using the 'sealed' keyword.

• They are often used when a class is not intended to be inherited or overridden.

• Sealed classes can have private constructors to prevent instantiation.

• Example: 'sealed class MyClass {}'

C# is a programming language used in .NET framework for developing Windows applications, web services, and more.

• C# is a programming language developed by Microsoft for building applications on the .NET framework

• .NET is a software framework developed by Microsoft for building and running Windows applications

• C# is widely used for developing web services, desktop applications, and more

• C# is an object-oriented language with features like type safety, garbage collection, and scala...read more

Defered Execution is a technique where the execution of a query or operation is delayed until it is actually needed.

• Defered Execution is used in LINQ queries to improve performance by delaying the execution of the query until the results are actually needed.

• It allows for more efficient use of resources by avoiding unnecessary computations.

• Examples of Defered Execution include using the .Where() method in LINQ to filter a collection, or using the .Take() method to limit the nu...read more

C# and database preparation for software engineering

• Learn C# syntax and object-oriented programming concepts

• Understand database design and SQL queries

• Practice using C# to interact with databases

• Familiarize yourself with Entity Framework and LINQ

• Stay up-to-date with new technologies and best practices

C# is a versatile and powerful programming language with a strong ecosystem and support for various platforms.

• C# is widely used for developing Windows applications, web applications, and games.

• It has a rich set of libraries and frameworks like .NET Core and Xamarin for cross-platform development.

• C# is a statically typed language, which helps catch errors at compile time and improve code quality.

Indexers in C# allow objects to be indexed like arrays, enabling objects to be accessed using square brackets.

• Indexers are special type of properties in C# that allow objects to be indexed like arrays.

• They are defined using 'this' keyword followed by square brackets and the index parameters.

• Indexers can be used to access elements of a collection or class using square brackets.

• Example: public string this[int index] { get { return myArray[index]; } set { myArray[index] = value;...read more

No, static constructors cannot have multiple arguments.

• Static constructors in C# do not take any arguments.

• They are used to initialize static data members or perform any necessary setup for the class.

• Example: public static MyClass() { // constructor code }

Core concepts in C# include classes, objects, inheritance, polymorphism, encapsulation, and abstraction.

• Classes are the building blocks of C# programs, used to define objects with properties and methods.

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

• Polymorphism enables objects to be treated as instances of their parent class, allowing for flexibility in code.

• Encapsulation involves bundling data and methods within a class to restrict access an...read more

The null coalescing operator (??) is used to provide a default value for nullable types if the value is null.

• Null coalescing operator (??) is used to return the left-hand operand if the operand is not null, otherwise it returns the right-hand operand.

• Example: int? x = null; int y = x ?? -1; // y will be -1 since x is null

• It is commonly used with nullable types to provide a default value if the nullable type is null.

C# (pronounced as C sharp) is a programming language developed by Microsoft for building a wide range of applications on the .NET framework.

• Developed by Microsoft

• Object-oriented programming language

• Used for building applications on the .NET framework

• Syntax similar to C++ and Java

A record in C# is a data structure that contains a fixed number of fields of different data types.

• Records are similar to classes but are immutable by default

• They are used to group related data together

• Records are value types and are compared by value rather than by reference

out and ref are used for passing arguments by reference, while partial classes allow splitting a class definition into multiple files.

• out keyword is used for passing arguments by reference and does not require the variable to be initialized before passing.

• ref keyword is used for passing arguments by reference and requires the variable to be initialized before passing.

• Partial classes allow splitting a class definition into multiple files, making it easier to manage large class...read more

Extension methods allow adding new methods to existing types without modifying the original type

• Extension methods are static methods that can be called as if they were instance methods of the extended type

• They are defined in static classes and must be in the same namespace as the extended type

• They are commonly used to add functionality to existing types or interfaces without modifying them directly

Advanced concepts in C# include LINQ, async/await, delegates, events, and generics.

• LINQ allows for querying data from different data sources using a uniform syntax.

• Async/await enables asynchronous programming, improving performance by not blocking the main thread.

• Delegates are type-safe function pointers that allow for callbacks and event handling.

• Events are a way for classes to provide notifications when something happens.

• Generics allow for writing reusable code by creating ...read more

C# is a powerful programming language with features like type safety, garbage collection, and LINQ.

• C# is a statically typed language, providing type safety and preventing runtime errors.

• It supports garbage collection, automatically managing memory allocation and deallocation.

• C# includes LINQ (Language Integrated Query) for querying data from different sources like databases and collections.

• It has support for asynchronous programming with async/await keywords.

• C# allows for obj...read more

Keywords in C# are reserved words that have special meaning and cannot be used as identifiers.

• Keywords are predefined and cannot be changed or redefined.

• Examples of keywords in C# include 'class', 'int', 'void', 'if', 'else', 'for', 'while', etc.

• Keywords are case-sensitive.

I have 3 years of experience working with C# in developing desktop applications and web services.

• Developed desktop applications using WinForms and WPF

• Created web services using ASP.NET Web API

• Familiar with LINQ, Entity Framework, and unit testing in C#

throw vs throw ex is used in exception handling in C#

• throw is used to rethrow the current exception without losing the original stack trace

• throw ex is used to throw a new exception while preserving the original exception information

• It is recommended to use throw without specifying ex to avoid losing important exception details