.Net Interview Questions

 

Core .NET Concepts

1. What is the .NET Framework?

   • The .NET Framework is a software development platform developed by Microsoft. It provides a controlled programming environment where software can be developed, installed, and executed on Windows-based operating systems.

2. Explain the differences between .NET Framework, .NET Core, and .NET 5/6.

   • .NET Framework: A Windows-only framework.
   • .NET Core: A cross-platform, open-source framework.
   • .NET 5/6: Unified platform that combines the best of .NET Core and .NET Framework, designed for cross-platform development.

3. What are CLR, CTS, and CLS?

   • CLR (Common Language Runtime): Executes .NET programs and provides services like memory management, garbage collection, and security.
   • CTS (Common Type System): Describes the data types that can be used in .NET applications.
   • CLS (Common Language Specification): A subset of CTS that provides a set of rules for language interoperability.

4. What is managed code?

   • Managed code is code that is executed by the CLR. It benefits from features such as garbage collection, exception handling, and type safety.

5. What is the purpose of the Global Assembly Cache (GAC)?

   • The GAC allows you to share assemblies across multiple applications. It is used to store assemblies that are intended to be used by several applications on the machine.

ASP.NET and Web Development

1. Explain the MVC (Model-View-Controller) pattern in ASP.NET.

   • MVC is a design pattern that separates an application into three main components: Model (data), View (UI), and Controller (business logic). This separation helps manage complex applications and promotes code reusability.

2. What is the difference between ASP.NET Web Forms and ASP.NET MVC?

   • Web Forms: Event-driven, drag-and-drop, rapid application development.
   • MVC: Separation of concerns, better control over HTML, support for test-driven development.

3. What are Razor views in ASP.NET MVC?

   • Razor is a markup syntax used to embed server-based code into web pages. It provides a cleaner and more fluent way to integrate C# code with HTML.

4. What are ASP.NET Web API and its use cases?

   • ASP.NET Web API is a framework for building HTTP services that can be consumed by various clients including browsers and mobile devices. It is used to create RESTful services.

C# Programming

1. Explain the difference between value types and reference types in C#.

   • Value types: Stored on the stack, contain the actual data. Examples: int, double.
   • Reference types: Stored on the heap, contain a reference to the data. Examples: class, interface.

2. What are delegates and events in C#?

   • Delegates: Type-safe function pointers used to call methods indirectly.
   • Events: A way for a class to notify other classes or objects when something of interest occurs.

3. What is LINQ and its benefits?

   • LINQ (Language Integrated Query) is a set of features in C# for querying data from different sources (databases, XML, collections). Benefits include readability, compile-time checking, and IntelliSense support.

4. Explain the concept of async and await in C#.

   • async: Modifies a method to perform asynchronous operations.
   • await: Pauses the execution of an async method until the awaited task completes, freeing the thread to perform other work.

Advanced Topics

1. What is dependency injection and why is it used?

   • Dependency injection is a design pattern used to implement IoC (Inversion of Control), allowing the creation of dependent objects outside of a class and providing those objects to a class. It enhances testability and maintainability.

2. Explain the concept of garbage collection in .NET.

   • Garbage collection is an automated process in .NET that frees up memory occupied by objects that are no longer in use. The CLR periodically performs garbage collection to reclaim memory.

3. What are generics in C#?

   • Generics allow you to define type-safe data structures without committing to actual data types. They provide better performance and type safety.

4. What is the difference between a task and a thread?

   • Task: Represents an asynchronous operation that can be managed by the task scheduler.
   • Thread: Represents a path of execution within a process. Threads can be managed manually.

.NET Libraries and Tools

1. What is Entity Framework and how does it work?

   • Entity Framework (EF) is an ORM (Object-Relational Mapper) for .NET. It allows developers to work with a database using .NET objects, eliminating the need for most of the data-access code developers usually need to write.

2. What is NuGet and how is it used?

   • NuGet is a package manager for .NET that simplifies the process of incorporating third-party libraries into a .NET application. It handles downloading, installing, and updating libraries and their dependencies.

3. Explain the role of middleware in ASP.NET Core.

   • Middleware are components in ASP.NET Core that form a pipeline to handle requests and responses. Each middleware component can either process the request or pass it to the next component in the pipeline.

4. What is the difference between synchronous and asynchronous programming?

   • Synchronous programming: Operations are performed sequentially, one after the other.
   • Asynchronous programming: Operations can run independently of the main program flow, allowing other operations to continue processing.