Top 50 OOPS C# Interview Questions - .NET

🚀 .NET Interview Mastery Bootcamp (3 Courses Included) 🎯Course 1: Top 500 .NET Interview Questions (with Quick Revision PDF Book) Topics: OOPS, C#, ASP.NET MVC, .NET Core, Web API, SQL, Coding Questions 🎯Course 2: .NET Interview Success Guide Topics: .NET Resume Template, HR/MR Questions, Salary Negotiation. 🎯Course 3: .NET Mock Interviews & .NET Revision Flashcards 10 .NET Mock Interviews for All Experience Levels (0-1 yr, 1-3 yrs, 3-6 yrs, 6+ yrs) 💥 Use Coupon Code: NEVERGIVEUP for 75% Off (Limited Time) 📩 For bootcamp queries mail me - [email protected] ✅ 100% 7-Days Money-Back Guarantee 👉 Click here for Bootcamp - https://www.interviewhappy.com/page/dotnetbootcamp 👉 For Just Course 1 or Outside India use below link: https://www.udemy.com/course/csharp-oops-mvc-asp-dotnet-core-webapi-sql-questions-mock-interviews/?couponCode=DOTNETOFFERJAN2025 📘 Quick Revision Book (PDF) – Top 500 .NET Interview Questions 🎉 50% Off – Limited Time Offer Already Applied! ✅ 100% 7-Days Money-Back Guarantee 📩 For queries mail me - [email protected] 👉 Get It Here: https://imojo.in/interviewhappy 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?