Top 50 OOPS C# Interview Questions for .NET 🚀

🔥 Crack Your Next .NET Interview

🚀 Get Interview-Ready in Just 7 Days

✅ You’ll Get 3 Courses in 1 Bootcamp (Book Included):

1️⃣ 500+ .NET Interview Q&A
🎥 Video Lectures + 📝Question List (Excel) + 📘PDF Book for Revision
Covers: OOPS, C#, ASP.NET MVC, .NET Core, Web API, SQL & Coding

2️⃣ Mock Interviews + Faster Revision Flashcards

3️⃣ Interview Success Kit
📝 .NET Resume Template + 👩‍💼 HR/MR Q&A + 💸 Salary Negotiation Secrets

💥Use Code: NEVERGIVEUP for 75% Off (Limited Time Only)
✅ 100% Risk-Free: 7-Day Money-Back Guarantee
📩 Queries - happy@interviewhappy.com

👉 Join Bootcamp or Get Book → https://www.interviewhappy.com/page/dotnetbootcamp

🌏 Outside India Users → https://www.interviewhappy.com/page/o-dotnet

👍 Wishing you ALL THE BEST for your interviews! Never Give Up!

This video contains the top 50 interview questions asked in interviews.
00:00 - Introduction
01:16 - Q1. What are the main concepts of OOPS? What are classes and objects?
07:18 - Q2. What is Inheritance? Why Inheritance is important?
10:33 - Q3. What are the different types of Inheritance?
14:38 – Q4. How to prevent a class from being Inherited?
16:22 – Q5. What is Abstraction?
19:30 – Q6. What is Encapsulation?
23:52 – Q7. What is Polymorphism and what are its types?
26:47 – Q8. What is Method Overloading? In how many ways a method can be overloaded?
30:41 – Q9. What is the difference between Overloading and Overriding?
34:45 – Q10. What is the difference between Method Overriding and Method Hiding?
37:37 – Q11. What are the advantages and limitations of OOPS?
41:31 – Q12. What is the difference between an Abstract class and an Interface (atleast 4)?
46:45 – Q13. When to use Interface and when Abstract class?
50:39 – Q14. Why to even create Interfaces?
54:38 – Q15. Do Interface can have a Constructor?
56:17 – Q16. Can you create an instance of an Abstract class or an Interface?
58:54 - Q17. What are Access Specifiers? What is the default access modifier in a class?
03:47 – Q18. What is Boxing and Unboxing?
01:06:35 – Q19. What is the difference between “String” and “StringBuilder”? When to use what?
01:10:12- Q20. What are the basic string operations in C#?
01:12:56- Q21. What are Nullable types?
01:14:42 – Q22. Explain Generics in C#? When and why to use them?
01:20:18 – Q23. How to implement Exception Handling in C#?
01:24:05 – Q24. Can we execute multiple Catch blocks?
01:25:35 – Q25. What is a Finally block and give an example when to use it?
01:27:22 – Q26. Can we have only “Try” block without “Catch” block?
01:28:45 – Q27. What is the difference between “throw ex” and “throw”?
01:33:14 – Q28. What are the Loop types in C#?
01:37.04 – Q29. What is the difference between “continue” and “break” statement?
01:40:52 – Q30. What is the difference between Array and ArrayList (atleast 2)?
01:43:39 - Q31. What is the difference between Arraylist and Hashtable?
01:45:23 – Q32. What are Collections in C# and what are their types?
01:48:49 – Q33. What is IEnumerable in C#?
01:52:15 – Q34. What is the difference between IEnumerable and IEnumerator in C#?
01:55:06 – Q35. What is the difference between IEnumerable and IQueryable in C#? Why to use IQueryable in sql queries?
01:58:30 – Q36. What is the difference between “out” and “ref” parameters?
02:05:06 – Q37. What is the purpose of “params” keyword?
02:07:04 – Q38. What is a Constructor and what are its types?
02:17:59 – Q39. When to use Private constructor?
02:19:27 – Q40. What are Extension Methods in C#? When to use them?
02:24:53 – Q41. What you mean by Delegate? When to use them?
02:29:35 – Q42. What are Multicast Delegates?
02:34:23 – Q43. What are Anonymous Delegates in C#?
02:36:37 – Q44. What are the differences between Events and Delegates?
02:40:28 – Q45. What is “this” keyword in C#? When to use it?
02:44:09 – Q46. What is the purpose of “using” keyword in C#?
02:48:42 – Q47. What is the difference between “is” and “as” operators?
02:52:09 – Q48. What is the difference between “Readonly” and “Constant” variables (atleast 3)?
02:57:35 – Q49. What is “Static” class? When to use it?
03:00:26 – Q50. What is the difference between “var” and “dynamic” in C#?
03:03:17 – Q51. What is Enum keyword used for?