Mastering .NET Interview Questions with Shivprasad Koirala's 6th Edition PDF

.NET Interview Questions and Answers

If you are a developer who wants to work with the .NET framework, you need to be prepared for the technical interview questions that you may face. The .NET framework is a platform that allows you to build, run, and deploy applications on Windows and the web. It supports multiple programming languages, such as C#, VB.NET, F#, etc., and provides a rich set of libraries and tools for developing various types of applications.

.net Interview Questions Shivprasad Koirala 6th Edition Pdf

In this article, we will cover some of the most common and important .NET interview questions and answers that you should know. We will divide them into three categories: basic, intermediate, and advanced. By the end of this article, you will have a better understanding of the .NET framework and how to ace your .NET interview.

Basic .NET Interview Questions

The basic .NET interview questions are designed to test your knowledge of the fundamental concepts and components of the .NET framework. You should be familiar with the following topics:

• Common Language Runtime (CLR)

• Common Type System (CTS)

• Common Language Specification (CLS)

• Just-in-time (JIT) compiler

• Microsoft Intermediate Language (MSIL)

• Managed code and unmanaged code

• Value types and reference types

• Boxing and unboxing

Here are some examples of basic .NET interview questions and answers:

Q: What is CLR?

A: CLR stands for Common Language Runtime. It is the core component of the .NET framework that provides a common execution environment for all .NET applications. It performs various functions, such as:

• Loading and executing assemblies

• Managing memory and garbage collection

• Enforcing security policies

• Handling exceptions

• Providing interoperability with other languages and platforms

• Supporting debugging and profiling

Q: What is CTS?

A: CTS stands for Common Type System. It is a set of rules that defines how types are declared, used, and managed in the .NET framework. It ensures that types are consistent across all .NET languages and can interoperate with each other. It also provides a common base class library that contains predefined types for common tasks.

Q: What is CLS?

A: CLS stands for Common Language Specification. It is a subset of CTS that defines a set of rules and guidelines that all .NET languages must follow to ensure compatibility and interoperability. For example, CLS specifies how identifiers are named, how data types are defined, how inheritance is implemented, etc.

Q: What is JIT?

A: JIT stands for Just-in-time compiler. It is a component of the CLR that converts the MSIL code into native machine code at run time. It optimizes the performance and memory usage of the .NET applications by compiling only the required methods and caching the results for future use.

Q: What is MSIL?

A: MSIL stands for Microsoft Intermediate Language. It is a low-level, platform-independent language that is generated by the .NET compilers from the source code. It contains instructions for the CLR to execute the .NET applications. It can be viewed using tools such as ILDASM (IL Disassembler) or ILASM (IL Assembler).

Q: What is the difference between managed code and unmanaged code in .NET?

A: Managed code is the code that is written in any .NET language and compiled into MSIL. It runs under the control and supervision of the CLR, which provides various services such as memory management, security, exception handling, etc. Unmanaged code is the code that is written in languages such as C or C++ and compiled into native machine code. It runs outside the scope of the CLR and directly interacts with the operating system or hardware.

Q: What is the difference between value types and reference types in .NET?

A: Value types are the types that store their data directly on the stack or in a structure. They are derived from the System.ValueType class. They are copied by value, which means that each variable has its own copy of the data. Examples of value types are int, bool, char, struct, enum, etc.

Reference types are the types that store their data on the heap and have a reference to it on the stack. They are derived from the System.Object class. They are copied by reference, which means that multiple variables can point to the same data. Examples of reference types are string, object, class, interface, delegate, array, etc.

Q: What are boxing and unboxing in .NET?

A: Boxing and unboxing are the processes of converting value types to reference types and vice versa.

Boxing is the process of wrapping a value type in an object and storing it on the heap. It is an implicit conversion that happens when a value type is assigned to an object variable or passed to a method that expects an object parameter.

Unboxing is the process of extracting a value type from an object and storing it on the stack. It is an explicit conversion that happens when an object variable is cast to a value type or passed to a method that expects a value type parameter.

Boxing and unboxing can affect the performance and memory usage of the .NET applications, so they should be avoided as much as possible.

Intermediate .NET Interview Questions

The intermediate .NET interview questions are designed to test your knowledge of the intermediate concepts and features of the .NET framework. You should be familiar with the following topics:

• ASP.NET

• MVC

• Web API

• LINQ

• Entity Framework

• Lambda expressions

• Delegates and events

• Generics

Here are some examples of intermediate .NET interview questions and answers:

Q: What is ASP.NET?

A: ASP.NET is a web development framework that allows you to create dynamic web applications using .NET languages and technologies. It provides various features and services, such as:

• Web Forms: A model that allows you to create web pages using controls and events

• MVC: A model that allows you to create web applications using separation of concerns and test-driven development

• Web API: A model that allows you to create RESTful web services using HTTP verbs and JSON or XML formats

• Web Pages: A model that allows you to create web pages using Razor syntax and HTML helpers

• SignalR: A library that enables real-time communication between web servers and clients using WebSockets or other protocols

• Identity: A framework that provides authentication and authorization services for web applications

• Caching: A technique that improves the performance and scalability of web applications by storing frequently used data in memory or disk

• Session State: A technique that preserves user-specific data across multiple requests or pages

• Validation: A technique that ensures user input meets certain criteria before processing it

• AJAX: A technique that enables partial page updates without reloading the entire page

Q: What is MVC?

A: MVC stands for Model-View-Controller. It is a design pattern that separates the logic and presentation of a web application into three components:

• Model: The component that represents the data and business logic of the application

• View: The component that displays the user interface and user input of the application

• Controller: The component that handles the user requests and interactions with the model and view

MVC provides several benefits, such as:

• Loose coupling: The components are independent and can be changed or tested without affecting each other

• Reusability: The components can be reused in different scenarios or applications

• Maintainability: The components are easier to maintain and debug due to their separation of concerns

• Testability: The components can be tested individually or as a whole using unit tests or integration tests

Q: What is Web API?

A: Web API is a framework that allows you to create RESTful web services using .NET languages and technologies. REST stands for Representational State Transfer, which is an architectural style that defines how resources are identified and manipulated using HTTP verbs (GET, POST, PUT, DELETE, etc.) and formats (JSON, XML, etc.). Web API provides various features and services, such as:

• Routing: A mechanism that maps the URL of a request to a specific controller action

• Model Binding: A mechanism that converts the request data into .NET objects that can be used by the controller action

• Model Validation: A mechanism that validates the request data against certain rules and annotations before processing it

• Content Negotiation: A mechanism that determines the best format to return the response data based on the request header or query string

• Filtering: A mechanism that allows you to apply custom logic or attributes to the controller actions or results, such as authentication, authorization, caching, logging, etc.

• Dependency Injection: A technique that allows you to inject dependencies into the controller classes using constructor parameters or properties

• Testing: A technique that allows you to test your web services using tools such as Postman, Fiddler, or HttpClient

Q: What is LINQ?

A: LINQ stands for Language Integrated Query. It is a feature that allows you to query various data sources using a common syntax and operators. It supports both query expression syntax and method syntax. It provides various benefits, such as:

• Intellisense: It provides code completion and error checking features in Visual Studio

• Type Safety: It ensures that the query results match the expected data types at compile time

• Performance: It optimizes the query execution by using deferred execution and lazy evaluation techniques

• Extensibility: It allows you to create custom query providers and operators for different data sources or scenarios

LINQ can be used to query various data sources, such as:

• LINQ to Objects: It allows you to query in-memory collections of objects using IEnumerable or IQueryable interfaces

• LINQ to SQL: It allows you to query relational databases using DataContext or Table classes

• LINQ to XML: It allows you to query XML documents using XElement or XDocument classes

• LINQ to Entities: It allows you to query entity models using DbContext or DbSet classes

• LINQ to DataSet: It allows you to query data sets using DataTable or DataRow classes

Q: What is Entity Framework?

A: Entity Framework is an object-relational mapper (ORM) that enables you to work with relational databases using .NET objects. It eliminates the need for writing SQL queries by providing a higher-level abstraction of the database schema. It supports various approaches, such as:

• Database First: It allows you to generate an entity model from an existing database using tools such as Entity Data Model Wizard or Entity Framework Designer

• Model First: It allows you to create an entity model using graphical tools such as Entity Framework Designer and then generate a database from it using tools such as Generate Database Wizard or Update Model Wizard

• Code First: It allows you to create an entity model using code conventions or annotations and then generate a database from it using tools such as Enable-Migrations or Update-Database

Entity Framework provides various features and services, such as:

• DbContext: A class that represents a connection to a database and a set of entity sets

• DbSet: A class that represents an entity set that can be queried or updated

• LINQ to Entities: A feature that allows you to query entity sets using LINQ syntax and operators

• Entity SQL: A feature that allows you to query entity sets using SQL-like syntax and operators

• Change Tracking: A feature that tracks the changes made to the entities and their relationships

• Save Changes: A feature that persists the changes made to the entities and their relationships to the database

• Migrations: A feature that allows you to update the database schema based on the changes made to the entity model

• Lazy Loading: A feature that loads the related entities on demand when they are accessed

• Eager Loading: A feature that loads the related entities along with the main entities using Include method

• Explicit Loading: A feature that loads the related entities explicitly using Load method

Q: What are lambda expressions in .NET?

A: Lambda expressions are anonymous functions that can be used to create delegates or expression trees. They have a concise and expressive syntax that consists of a parameter list, a => operator, and a body. They can be used for various purposes, such as:

• LINQ queries: They can be used as arguments for LINQ methods such as Where, Select, OrderBy, etc.

• Event handlers: They can be used to handle events without creating named methods

• Asynchronous programming: They can be used as callbacks for async/await keywords or Task.Run method

• Closure: They can capture the variables from the outer scope and use them in the inner scope

Q: What are delegates and events in .NET?

A: Delegates are types that represent references to methods with a specific parameter list and return type. They can be used to invoke methods dynamically, pass methods as arguments, or create callback mechanisms. They can be declared using delegate keyword or predefined types such as Action, Func, Predicate, etc.

Events are members that enable a class or object to notify other classes or objects when something of interest occurs. They can be declared using event keyword or predefined types such as EventHandler, EventHandler, etc. They can be raised using += operator or -= operator.

Q: What are generics in .NET?

A: Generics are features that enable you to create classes, methods, interfaces, or delegates that can work with different types of data without repeating code. They provide type safety, performance, and reusability benefits. They can be declared using syntax or predefined types such as List, Dictionary, etc.

Advanced .NET Interview Questions

The advanced .NET interview questions are designed to test your knowledge of the advanced concepts and techniques of the .NET framework. You should be familiar with the following topics:

• Async/await keywords

• Task Parallel Library (TPL)

• Parallel LINQ (PLINQ)

• Reflection

• Attributes

• Exception handling

• Dependency injection

• Unit testing

Here are some examples of advanced .NET interview questions and answers:

Q: What are async/await keywords in .NET?

A: Async/await keywords are features that enable you to write asynchronous code in a synchronous manner. They allow you to perform non-blocking operations without blocking the main thread or creating callbacks. They can be used for various scenarios, such as:

• I/O-bound operations: They can be used to read or write files, network streams, databases, etc. without waiting for them to complete

• CPU-bound operations: They can be used to perform intensive computations or algorithms on a separate thread without affecting the responsiveness of the UI thread

• Mixed operations: They can be used to combine I/O-bound and CPU-bound operations in a single method using Task.Run method or Task.WhenAll method

Q: What is Task Parallel Library (TPL) in .NET?

can run asynchronously and concurrently on multiple threads. TPL provides various benefits, such as:

• Abstraction: It hides the low-level details of thread creation and management and provides a higher-level API for creating and manipulating tasks

• Scalability: It optimizes the use of system resources and adjusts the degree of parallelism based on the workload and environment

• Cancellation: It provides a mechanism to cancel one or more tasks using CancellationTokenSource and CancellationToken classes

• Continuation: It provides a mechanism to execute one or more tasks after another task completes using ContinueWith method or await keyword

• Exception handling: It provides a mechanism to handle exceptions thrown by one or more tasks using AggregateException class or try/catch blocks

Q: What is Parallel LINQ (PLINQ) in .NET?

A: Parallel LINQ (PLINQ) is a feature that enables you to execute LINQ queries in parallel using multiple threads. It can improve the performance and scalability of data-intensive applications by taking advantage of multicore processors. It can be used for various scenarios, such as:

• Filtering: It can be used to apply a predicate to a large collection of data using Where method or query expression syntax

• Projection: It can be used to transform a large collection of data into another form using Select method or query expression syntax

• Aggregation: It can be used to compute a single value from a large collection of data using methods such as Sum, Count, Average, Max, Min, etc.

• Joining: It can be used to combine two large collections of data based on a common key using methods such as Join, GroupJoin, Zip, etc.

• Ordering: It can be used to sort a large collection of data using methods such as OrderBy, ThenBy, Reverse, etc.

PLINQ can be enabled by using AsParallel extension method on any IEnumerable source. It can be customized by using various options and methods, such as:

• WithDegreeOfParallelism: It allows you to specify the maximum number of threads to use for the query

• WithExecutionMode: It allows you to specify whether to use parallel execution only if it is faster than sequential execution or always use parallel execution

• WithMergeOptions: It allows you to specify how the results are merged from multiple threads into a single output sequence

• AsOrdered: It allows you to preserve the order of the source sequence in the output sequence

• AsSequential: It allows you to switch back to sequential execution for some operations that do not benefit from parallel execution

• ForAll: It allows you to perform an action on each element of the output sequence in parallel without returning a result

Q: What is Reflection in .NET?

A: Reflection is a feature that enables you to inspect and manipulate the metadata and behavior of types and assemblies at run time. It can be used for various purposes, such as:

• Loading assemblies dynamically using Assembly.Load or Assembly.LoadFrom methods

• Getting information about types and members using Type.GetType or Assembly.GetTypes methods

• Creating instances of types using Activator.CreateInstance or ConstructorInfo.Invoke methods

• Invoking methods or properties using MethodInfo.Invoke or PropertyInfo.GetValue methods

• Setting fields or properties using FieldInfo.SetValue or PropertyInfo.SetValue methods

• Creating custom attributes and applying them to types or members using Attribute class or CustomAttributeBuilder class

Finding attributes applied to types or members using Attribute.GetCustomAttribute or MemberInfo.GetCustomAttrib