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Top 50 C# Interview Questions and Answers

10/Oct/2020 | 15 minutes to read

Here is a List of essential C# Interview Questions and Answers for Freshers and mid level of Experienced Professionals. All answers for these C# questions are explained in a simple and easiest way. These questions will help you to clear your next Job interview.

C# Interview Questions

C# Interview Questions and Answers

These interview questions are targeted for C# Programming language. A .NET Developer should know the answers of these C# questions to clear the interview.

1. What is latest version of C# with features?

C# 1.0 released in 2002. And latest version of C# is 9.0. For more you can visit Microsoft official site Releases . There are many new features in C# 9.0. For more you can visit What's new in C# 9.0.

2. What is the difference between const, readonly and static keyword?

3. What is the difference between in, ref and out keywords?

4. What is the Inheritance? Why C# does not support multiple Inheritance?

5. What is method shadowing or method hiding in C#?

6. Differentiate Var, Object and Dynamic keywords in C#.

7. Can Virtual or Abstract member be declare private in C#?

No, It will throw compile time error.

virtual void display() // will throw error here
        // Implementation


8. What is Boxing and Unboxing in C# ?

9. What is Method Overloading in C#?

10. What is Value Type and Reference Type in C#?

10. What are the new features in C# 8.0?

To know more about C# 8.0 new features visit What's new in C# 8.0

11. What is Abstraction and Encapsulation in C#? How will you differentiate them?

12. What is the deference between Abstract class and Interface in C#? What is the need of these?

13. What is Polymorphism? What is static and Dynamic Polymorphism in C#?

14. What will be output of below program? Error Line will throw any error in below code?

  class A
       public virtual void display()
        { Console.WriteLine("A - display method"); }
    class B:A
        public override void display()
        { Console.WriteLine("B - display method"); }
    class Test
        static void Main()
            A obj = new A();

            A obj1 = new B();

            B o = new B();
            // B ob = new A();  Error Line

Output: 'Error Line' will throw error - Cannot implicitly convert type 'A' to 'B'. An explicit conversion exists (are you missing a cast?).
Output will be as below.
A - display method
B - display method
B - display method

16. Can Abstract class has constructor in C#? Below code will compile or not, or it will give any error in Error line 1 or 2.

class A
       public virtual void display()
            Console.WriteLine("A - display");
        public virtual void disp()
            Console.WriteLine("A - disp");
abstract class ab :A
        public ab()
        { }
        public abstract override void display(); Error Line 1

        public sealed override void disp()  Error Line 2
            Console.WriteLine("disp is sealed now.");

Solution: Abstract class can contain the constructor. Constructor is used to instantiate the class instance members in C#.
Above code will compile successfully. In C#, we can add Abstract and Sealed keywords with the override keyword.

17. What is volatile keyword in C#?

18. What is the use of sealed keyword in C#?

19. Explain string interpolation in C#.

20. What is the difference between abstract and virtual keywords?

20. What are the new features in C# 7.0?

To know more about C# 7.0 new features visit What's new in C# 7.3

21. What is Covariance and Contravariance in C#?

Fore more Covariance and Contravariance in C#

22. What will be output of following program? or will throw any error?

    public void display()

    int x = 0;
    int y = 10;
    int z = y / x;
    catch (Exception)
    catch (DivideByZeroException)


23. What points (related to try, catch and finally) you should keep in mind while implementing exception handling in C#?

24. What is Generics in C#? What are the benefits of Generics?

25. What is IDisposable Interface in C#? How to implement dispose method?

26. Explain Dispose Pattern in C#.

27. How does Garbage Collection work in C#? Explain Generations.

28. What is using statement in C#?

29. What is Finalizers in C#? Explain SupressFinalize() method.

30. What will be output of below code?

    int a = 0;
    int x = 4;
    int y ;
    y = x / a;
    catch (Exception e)
    Console.WriteLine("inner ex");
    //throw;   // Line 1
    //throw e;   // Line 2
    //throw new Exception("divide by 0");  // Line 3

    catch (Exception ex)
    Console.WriteLine("outer ex");
    throw ex;

31. What is Equals method?

32. What is the difference between Equality operator == and Equals() method in C#?

33. What is the use of new keyword rather than creating new object in C#?

34. What is the extension methods in C#?

35. Explain Partial class and methods.

36. In how many ways can you pass parameters in C#?

37. What is the difference between EXE and DLL file?

38. What is DLL hell Problem?

39. What is Asynchronous Programming?

40. What is async and await in C#?

44. What are the new features in C# 6.0?

To know more about C# 6.0 new features visit What's new in C# 6.0

Some General Interview Questions for C#

1. How much will you rate your self in C#?

When you attend an interview, Interviewer may ask you to rate your self in specific Technology like C#, So It's depend on your knowledge and work experience in C#.

2. What challenges did you face while working on C#?

This question may be specific to your technology and completely depends on your past work experience. So you need to just explain the challenges you faced related to C# in your Project.

3. What was your role in last Project related to C#?

It's based on your role and responsibilities assigned to you and what functionality you implemented using C# in your project. This question is generally asked in every interview.

4. How much experience do you have in C#?

Here you can tell about your overall work experience on C#.

5. Have you done any C# Certification or Training?

It's depend on candidate like you have done any C# training or certification. Certifications or trainings are not essential but good to have.


We have covered some frequently asked C# Interview Questions and Answers to help you for your Interview. All these Essential C# Interview Questions are targeted for mid level of experienced Professionals and freshers.
While attending any C# Interview if you face any difficulty to answer any question please write to us at Our IT Expert team will find the best answer and will update on portal. In case if we find any new C# questions, we will update the same here.

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