Commonly Asked Interview Questions

1. Basic C# Concepts:

• What is C#?
• What are the key features of C#?
• Explain value types and reference types in C#.
• What are the differences between const and readonly in C#?.. more

2. Object-Oriented Programming (OOP):

• What is OOP, and what are its core principles?
• Explain the concepts of inheritance, encapsulation, polymorphism, and abstraction.
• How does C# support multiple inheritance?
• What are access modifiers in C# (e.g., public, private, protected, internal, protected internal)?

3. C# Language Features:

• Describe the difference between var and explicit data types in C#.
• What are nullable value types, and how do you use them?
• How does C# handle exceptions, and what are some common exception handling mechanisms?

4. LINQ:

• What is LINQ, and what problems does it solve?
• Explain the difference between method syntax and query syntax in LINQ.
• What are some common LINQ operators, and how are they used?

5. .NET Framework and .NET Core:

• What is the .NET Framework, and what is .NET Core?
• What are the main differences between .NET Framework and .NET Core?
• Explain the advantages of .NET Core.

6. ASP.NET Core:

• What is ASP.NET Core, and how is it different from ASP.NET?
• Describe the middleware concept in ASP.NET Core.
• Explain the Razor view engine and how it relates to MVC in ASP.NET Core.

7. Entity Framework Core:

• What is Entity Framework Core (EF Core)?
• How do you define models and relationships in EF Core?
• Explain the different approaches to querying data in EF Core.

8. Web API:

• What is a Web API, and how does it differ from traditional web services?
• Explain the main components of ASP.NET Core Web API (e.g., controllers, routing).
• How do you handle HTTP verbs (GET, POST, PUT, DELETE) in a Web API?

9. Dependency Injection:

• What is dependency injection, and why is it important?
• How do you implement dependency injection in ASP.NET Core?

10. Threading and Asynchronous Programming:

• What is the difference between a thread and a process?
• Explain the concept of asynchronous programming in C# using async and await.
• How do you handle thread synchronization and avoid race conditions?

11. Unit Testing:

• What is unit testing, and why is it important?
• Describe the role of testing frameworks like MSTest, NUnit, or xUnit.

12. Design Patterns:

• Explain the Singleton, Factory, and Dependency Injection patterns.
• How do these patterns help in writing maintainable and scalable code?

13. Security:

• What are common security risks in web applications, and how do you mitigate them?
• Describe Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF) attacks.

Remember to practice answering these questions and be ready to demonstrate your coding skills if necessary. Good luck with your interviews!