{"id":6047,"date":"2025-03-16T15:17:20","date_gmt":"2025-03-16T15:17:20","guid":{"rendered":"https:\/\/www.hirist.tech\/blog\/?p=6047"},"modified":"2025-12-29T11:35:38","modified_gmt":"2025-12-29T11:35:38","slug":"top-30-c-oops-interview-questions-and-answers","status":"publish","type":"post","link":"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/","title":{"rendered":"Top 30+ C# OOPs Interview Questions and Answers"},"content":{"rendered":"\n<p>Are you preparing for a C# OOPs interview? Object-oriented programming (OOP) is at the core of C#, and interviewers often test your understanding of its principles, concepts, and real-world applications. In this guide, we\u2019ve compiled 30+ essential C# OOPs interview questions and answers to help you tackle technical rounds with confidence.<\/p>\n\n\n\n<p><strong>Fun Fact:<\/strong> C# developers in India with 1 to 4 years of experience earn between \u20b92 lakh and \u20b912 lakh per year.<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_65 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title \" >Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#Basic_C_OOPs_Interview_Questions\" title=\"Basic C# OOPs Interview Questions\">Basic C# OOPs Interview Questions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#OOPs_Concepts_C_Interview_Questions\" title=\"OOPs Concepts C# Interview Questions\">OOPs Concepts C# Interview Questions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#C_Object_Oriented_Interview_Questions_for_Freshers\" title=\"C# Object Oriented Interview Questions for Freshers\">C# Object Oriented Interview Questions for Freshers<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#C_OOPs_Interview_Questions_for_Experienced\" title=\"C# OOPs Interview Questions for Experienced\">C# OOPs Interview Questions for Experienced<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#OOPs_Interview_Questions_C_for_5_Years_Experienced\" title=\"OOPs Interview Questions C# for 5 Years Experienced\">OOPs Interview Questions C# for 5 Years Experienced<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#OOPs_Interview_Questions_C_for_7_Years_Experienced\" title=\"OOPs Interview Questions C# for 7 Years Experienced\">OOPs Interview Questions C# for 7 Years Experienced<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#C_OOPs_Interview_Questions_for_10_Years_Experienced\" title=\"C# OOPs Interview Questions for 10 Years Experienced\">C# OOPs Interview Questions for 10 Years Experienced<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#Advanced_C_Object_Oriented_Programming_Interview_Questions\" title=\"Advanced C# Object Oriented Programming Interview Questions\">Advanced C# Object Oriented Programming Interview Questions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#OOPs_Tricky_Interview_Questions_C\" title=\"OOPs Tricky Interview Questions C#\">OOPs Tricky Interview Questions C#<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#C_OOps_Scenario_Based_Interview_Questions\" title=\"C# OOps Scenario Based Interview Questions\">C# OOps Scenario Based Interview Questions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/www.hirist.tech\/blog\/top-30-c-oops-interview-questions-and-answers\/#Wrapping_Up\" title=\"Wrapping Up\">Wrapping Up<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Basic_C_OOPs_Interview_Questions\"><\/span>Basic C# OOPs Interview Questions<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Here is a list of basic C Sharp OOPs interview questions and answers:<\/p>\n\n\n\n<ol>\n<li><strong>What is the difference between a class and an object in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>A class is a blueprint that defines properties and behaviours, while an object is an instance of a class with its own values for those properties.<\/p>\n\n\n\n<ol start=\"2\">\n<li><strong>What is inheritance in C#, and how does it promote code reusability?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Inheritance allows a child class to inherit methods and properties from a parent class, reducing redundant code and promoting reusability.<\/p>\n\n\n\n<p><strong>Example:<\/strong><\/p>\n\n\n\n<p>class Animal { public void Eat() { Console.WriteLine(&#8220;Eating&#8221;); } }<\/p>\n\n\n\n<p>class Dog : Animal { public void Bark() { Console.WriteLine(&#8220;Barking&#8221;); } }<\/p>\n\n\n\n<p>Here, Dog can use Eat() from Animal without redefining it.<\/p>\n\n\n\n<ol start=\"3\">\n<li><strong>Can you explain polymorphism in C# with an example?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Polymorphism allows methods to behave differently based on the object that calls them.<\/p>\n\n\n\n<ul>\n<li><strong>Method Overloading:<\/strong><\/li>\n<\/ul>\n\n\n\n<p>class MathOperations {<\/p>\n\n\n\n<p>public int Add(int a, int b) =&gt; a + b;<\/p>\n\n\n\n<p>public double Add(double a, double b) =&gt; a + b;<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<ul>\n<li><strong>Method Overriding:<\/strong><\/li>\n<\/ul>\n\n\n\n<p>class Parent { public virtual void Show() { Console.WriteLine(&#8220;Parent&#8221;); } }<\/p>\n\n\n\n<p>class Child : Parent { public override void Show() { Console.WriteLine(&#8220;Child&#8221;); } }<\/p>\n\n\n\n<ol start=\"4\">\n<li><strong>What is the difference between an abstract class and an interface in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><strong>Feature<\/strong><\/td><td><strong>Abstract Class<\/strong><\/td><td><strong>Interface<\/strong><\/td><\/tr><tr><td><strong>Definition<\/strong><\/td><td>Can have both method definitions and implementations<\/td><td>Only method signatures, no implementations (until C# 8.0)<\/td><\/tr><tr><td><strong>Multiple Inheritance<\/strong><\/td><td>Cannot be inherited by multiple classes<\/td><td>Can be implemented by multiple classes<\/td><\/tr><tr><td><strong>Fields and Properties<\/strong><\/td><td>Can have fields, properties, and constructors<\/td><td>Cannot have instance fields (only static fields from C# 8.0)<\/td><\/tr><tr><td><strong>Access Modifiers<\/strong><\/td><td>Methods can have different access modifiers<\/td><td>All members are public by default<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"OOPs_Concepts_C_Interview_Questions\"><\/span>OOPs Concepts C# Interview Questions<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>You might also be asked about OOPs concept in C# interview questions. Here are some common ones:<\/p>\n\n\n\n<ol start=\"5\">\n<li><strong>What is encapsulation, and how is it implemented in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>This is one of the most important C# OOPs concepts interview questions.<\/p>\n\n\n\n<p>Encapsulation means restricting direct access to object data and modifying it through methods. It is implemented using private fields with public properties:<\/p>\n\n\n\n<p>class Person {<\/p>\n\n\n\n<p>private string name;<\/p>\n\n\n\n<p>public string Name {<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp; get { return name; }<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp; set { if (value.Length &gt; 0) name = value; }<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<ol start=\"6\">\n<li><strong>How does abstraction differ from encapsulation in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<ul>\n<li><strong>Encapsulation<\/strong> hides internal state and allows controlled access through methods\/properties.<\/li>\n\n\n\n<li><strong>Abstraction<\/strong> hides complex implementation details and provides a simple interface (achieved via abstract classes or interfaces).<\/li>\n<\/ul>\n\n\n\n<ol start=\"7\">\n<li><strong>What are access modifiers in C#, and how do they control access to class members?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Access modifiers define visibility of members:<\/p>\n\n\n\n<ul>\n<li><strong>public<\/strong> (accessible everywhere)<\/li>\n\n\n\n<li><strong>private<\/strong> (accessible only within the class)<\/li>\n\n\n\n<li><strong>protected<\/strong> (accessible within the class and derived classes)<\/li>\n\n\n\n<li><strong>internal<\/strong> (accessible within the same assembly)<\/li>\n\n\n\n<li><strong>protected internal<\/strong> (accessible within the same assembly or derived classes)<\/li>\n\n\n\n<li><strong>private protected<\/strong> (accessible within the same class or derived classes in the same assembly)<\/li>\n<\/ul>\n\n\n\n<ol start=\"8\">\n<li><strong>What is the purpose of interfaces in C#, and how do they differ from abstract classes?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>An interface defines only method signatures, while an abstract class can have both method signatures and implementations.<\/p>\n\n\n\n<p>interface IAnimal { void Speak(); }<\/p>\n\n\n\n<p>class Dog : IAnimal { public void Speak() { Console.WriteLine(&#8220;Bark&#8221;); } }<\/p>\n\n\n\n<p>An interface allows multiple inheritance, unlike abstract classes.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"C_Object_Oriented_Interview_Questions_for_Freshers\"><\/span>C# Object Oriented Interview Questions for Freshers<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Let\u2019s go through some frequently-asked C# OOPs interview questions and answers for freshers:<\/p>\n\n\n\n<ol start=\"9\">\n<li><strong>What is a constructor in C#, and how is it different from a method?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>A constructor initializes an object when it is created. It has the same name as the class and does not return a value.<\/p>\n\n\n\n<p>class Car {<\/p>\n\n\n\n<p>public string Model;<\/p>\n\n\n\n<p>public Car(string model) { Model = model; }<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<ol start=\"10\">\n<li><strong>Can you explain method overloading with an example in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Method overloading allows multiple methods with the same name but different parameters.<\/p>\n\n\n\n<p>class MathOps {<\/p>\n\n\n\n<p>public int Multiply(int a, int b) =&gt; a * b;<\/p>\n\n\n\n<p>public double Multiply(double a, double b) =&gt; a * b;<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<ol start=\"11\">\n<li><strong>What is method overriding, and how is it achieved in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Method overriding allows a derived class to provide a different implementation for a method in the base class using the override keyword.<\/p>\n\n\n\n<p>class Base { public virtual void Show() { Console.WriteLine(&#8220;Base&#8221;); } }<\/p>\n\n\n\n<p>class Derived : Base { public override void Show() { Console.WriteLine(&#8220;Derived&#8221;); } }<\/p>\n\n\n\n<ol start=\"12\">\n<li><strong>What is the significance of the &#8216;base&#8217; keyword in C# inheritance?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>The base keyword is used to call base class constructors or methods from a derived class.<\/p>\n\n\n\n<p>class Parent { public Parent() { Console.WriteLine(&#8220;Parent Constructor&#8221;); } }<\/p>\n\n\n\n<p>class Child : Parent { public Child() : base() { Console.WriteLine(&#8220;Child Constructor&#8221;); } }<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"C_OOPs_Interview_Questions_for_Experienced\"><\/span>C# OOPs Interview Questions for Experienced<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>If you are an experience candidate, you might come across such C# OOPs interview questions:<\/p>\n\n\n\n<ol start=\"13\">\n<li><strong>How do you implement the singleton design pattern in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>The Singleton pattern restricts a class to only one instance and provides a global access point. A thread-safe implementation is crucial for multi-threaded environments.<\/p>\n\n\n\n<p>public sealed class Singleton {<\/p>\n\n\n\n<p>private static readonly Lazy&lt;Singleton&gt; instance = new(() =&gt; new Singleton());<\/p>\n\n\n\n<p>private Singleton() { }<\/p>\n\n\n\n<p>public static Singleton Instance =&gt; instance.Value;<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<ol start=\"14\">\n<li><strong>What is dependency injection, and how is it used in C# applications?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Dependency Injection (DI) allows passing dependencies into a class rather than creating them inside the class. It improves testability and maintainability.<\/p>\n\n\n\n<p><strong>Example using IoC Container (ASP.NET Core Recommended Approach):<\/strong><\/p>\n\n\n\n<p>interface ILogger { void Log(string message); }<\/p>\n\n\n\n<p>class ConsoleLogger : ILogger { public void Log(string message) =&gt; Console.WriteLine(message); }<\/p>\n\n\n\n<p>class Service {<\/p>\n\n\n\n<p>private readonly ILogger _logger;<\/p>\n\n\n\n<p>public Service(ILogger logger) { _logger = logger; }<\/p>\n\n\n\n<p>public void Process() { _logger.Log(&#8220;Processing&#8230;&#8221;); }<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<p>\/\/ Registering Dependencies in IoC Container<\/p>\n\n\n\n<p>var services = new ServiceCollection();<\/p>\n\n\n\n<p>services.AddScoped&lt;ILogger, ConsoleLogger&gt;();<\/p>\n\n\n\n<p>services.AddScoped&lt;Service&gt;();<\/p>\n\n\n\n<p>\/\/ Resolving Dependencies<\/p>\n\n\n\n<p>var provider = services.BuildServiceProvider();<\/p>\n\n\n\n<p>var service = provider.GetRequiredService&lt;Service&gt;();<\/p>\n\n\n\n<p>service.Process();<\/p>\n\n\n\n<ol start=\"15\">\n<li><strong>Can you explain the SOLID principles and how they apply to C# OOP design?<\/strong><\/li>\n<\/ol>\n\n\n\n<ul>\n<li><strong>S<\/strong>: Single Responsibility \u2013 A class should have one responsibility.<\/li>\n\n\n\n<li><strong>O<\/strong>: Open\/Closed \u2013 Open for extension, closed for modification.<\/li>\n\n\n\n<li><strong>L<\/strong>: Liskov Substitution \u2013 A derived class should be replaceable for its base class.<\/li>\n\n\n\n<li><strong>I<\/strong>: Interface Segregation \u2013 Clients should not depend on unused interfaces.<\/li>\n\n\n\n<li><strong>D<\/strong>: Dependency Inversion \u2013 Depend on abstractions, not concrete implementations.<\/li>\n<\/ul>\n\n\n\n<ol start=\"16\">\n<li><strong>What are delegates in C#, and how are they used to implement event handling?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>A delegate is a type that references a method.<\/p>\n\n\n\n<p>delegate void MyDelegate(string message);<\/p>\n\n\n\n<p>class Program {<\/p>\n\n\n\n<p>static void PrintMessage(string msg) =&gt; Console.WriteLine(msg);<\/p>\n\n\n\n<p>static void Main() {<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp; MyDelegate del = PrintMessage;<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp; del(&#8220;Hello, Delegates!&#8221;);<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<p>Delegates are widely used in events and callbacks in C#.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"OOPs_Interview_Questions_C_for_5_Years_Experienced\"><\/span>OOPs Interview Questions C# for 5 Years Experienced<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>These are some common C# Object Oriented interview questions for professionals with 5 years of experience:<\/p>\n\n\n\n<ol start=\"17\">\n<li>Implement a generic repository pattern in C#.\u200b<\/li>\n\n\n\n<li>Describe a challenging C# project you worked on and how you applied OOP principles to solve problems.\u200b<\/li>\n\n\n\n<li>How do you approach learning new technologies or frameworks in the context of C# development?<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"OOPs_Interview_Questions_C_for_7_Years_Experienced\"><\/span>OOPs Interview Questions C# for 7 Years Experienced<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Here are C# Object Oriented Programming interview questions for candidates with 7 years of experience:<\/p>\n\n\n\n<ol start=\"20\">\n<li>Design a C# application demonstrating the use of the factory design pattern.\u200b<\/li>\n\n\n\n<li>Can you discuss a time when you had to refactor existing C# code to improve performance or maintainability?\u200b<\/li>\n\n\n\n<li>How do you mentor junior developers in understanding and applying OOP concepts in C#?<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"C_OOPs_Interview_Questions_for_10_Years_Experienced\"><\/span>C# OOPs Interview Questions for 10 Years Experienced<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>These interview questions on OOPs C# are commonly asked to senior-level candidates with around 10 years of experience:<\/p>\n\n\n\n<ol start=\"23\">\n<li>Architect a C# solution that utilizes microservices while adhering to OOP principles.\u200b<\/li>\n\n\n\n<li>Describe your experience in leading a team to develop a complex C# application using OOP methodologies.\u200b<\/li>\n\n\n\n<li>How do you handle conflicts within your development team, especially when deciding on design patterns or OOP approaches?<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Advanced_C_Object_Oriented_Programming_Interview_Questions\"><\/span>Advanced C# Object Oriented Programming Interview Questions<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Here are some advanced C# OOPs interview questions and answers:<\/p>\n\n\n\n<ol start=\"26\">\n<li><strong>What is reflection in C#, and how can it be used to inspect metadata at runtime?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Reflection allows runtime type inspection and dynamic method invocation. It\u2019s used for accessing assembly metadata, inspecting types, and working with attributes.<\/p>\n\n\n\n<p><strong>Example:<\/strong><\/p>\n\n\n\n<p>Type type = typeof(MyClass);<\/p>\n\n\n\n<p>foreach (var method in type.GetMethods()) {<\/p>\n\n\n\n<p>Console.WriteLine(method.Name);<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<p>It\u2019s commonly used in plugins, serializers, and testing frameworks.<\/p>\n\n\n\n<ol start=\"27\">\n<li><strong>Can you explain covariance and contravariance in C# with respect to delegates and generics?<\/strong><\/li>\n<\/ol>\n\n\n\n<ul>\n<li><strong>Covariance (out)<\/strong> allows returning a more derived type.<\/li>\n\n\n\n<li><strong>Contravariance (in)<\/strong> allows passing a more generic type.<\/li>\n<\/ul>\n\n\n\n<p><strong>Example:<\/strong><\/p>\n\n\n\n<p>Func&lt;object&gt; covariant = () =&gt; &#8220;Hello&#8221;;&nbsp; \/\/ Covariance<\/p>\n\n\n\n<p>Action&lt;string&gt; contravariant = (string s) =&gt; Console.WriteLine(s);&nbsp; \/\/ Contravariance<\/p>\n\n\n\n<p>Used in delegates and generics for flexibility.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"OOPs_Tricky_Interview_Questions_C\"><\/span>OOPs Tricky Interview Questions C#<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>You might also come across tricky interview questions on OOPs C# like these:<\/p>\n\n\n\n<ol start=\"28\">\n<li><strong>How does the &#8216;this&#8217; keyword differ from the &#8216;base&#8217; keyword in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<ul>\n<li>this refers to the current instance of a class.<\/li>\n\n\n\n<li>base refers to the parent class and is used to call its methods or constructors.<\/li>\n<\/ul>\n\n\n\n<p><strong>Example:<\/strong><\/p>\n\n\n\n<p>class Parent { public void Show() { Console.WriteLine(&#8220;Parent&#8221;); } }<\/p>\n\n\n\n<p>class Child : Parent {<\/p>\n\n\n\n<p>public void Display() { base.Show(); }&nbsp; \/\/ Calls Parent&#8217;s method<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<ol start=\"29\">\n<li><strong>Can you explain the difference between &#8216;finalize&#8217; and &#8216;dispose&#8217; methods in C#?<\/strong><\/li>\n<\/ol>\n\n\n\n<ul>\n<li>Finalize() is called by the garbage collector and cannot be explicitly invoked.<\/li>\n\n\n\n<li>Dispose() is manually called to release unmanaged resources.<\/li>\n<\/ul>\n\n\n\n<p><strong>Example:<\/strong><\/p>\n\n\n\n<p>class MyClass : IDisposable {<\/p>\n\n\n\n<p>public void Dispose() { Console.WriteLine(&#8220;Resources released&#8221;); }<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"C_OOps_Scenario_Based_Interview_Questions\"><\/span>C# OOps Scenario Based Interview Questions<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Here are some scenario-based OOPs interview questions C# with example:<\/p>\n\n\n\n<ol start=\"30\">\n<li><strong>How would you design a plugin architecture in C# to allow for dynamic feature addition?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Plugins are loaded dynamically using Reflection and Interfaces.<\/p>\n\n\n\n<p><strong>Example:<\/strong><\/p>\n\n\n\n<p>Assembly assembly = Assembly.LoadFrom(&#8220;Plugin.dll&#8221;);<\/p>\n\n\n\n<p>Type type = assembly.GetType(&#8220;PluginNamespace.PluginClass&#8221;);<\/p>\n\n\n\n<p>object instance = Activator.CreateInstance(type);<\/p>\n\n\n\n<p>Each plugin implements a common interface, allowing easy integration.<\/p>\n\n\n\n<ol start=\"31\">\n<li><strong>How would you handle versioning in a C# application to maintain backward compatibility?<\/strong><\/li>\n<\/ol>\n\n\n\n<p>Versioning is critical to avoid breaking changes in applications, especially Web APIs.<\/p>\n\n\n\n<ul>\n<li><strong>Use API Versioning in ASP.NET Core<\/strong><\/li>\n<\/ul>\n\n\n\n<p>[ApiVersion(&#8220;1.0&#8221;)]<\/p>\n\n\n\n<p>[Route(&#8220;api\/v{version:apiVersion}\/[controller]&#8221;)]<\/p>\n\n\n\n<p>public class UsersController : ControllerBase {<\/p>\n\n\n\n<p>[HttpGet]<\/p>\n\n\n\n<p>public IActionResult GetUsers() =&gt; Ok(new { Message = &#8220;Users v1&#8221; });<\/p>\n\n\n\n<p>}<\/p>\n\n\n\n<ul>\n<li><strong>Mark Deprecated Methods with [Obsolete]<\/strong><\/li>\n<\/ul>\n\n\n\n<p>[Obsolete(&#8220;Use NewMethod() instead&#8221;)]<\/p>\n\n\n\n<p>public void OldMethod() { }<\/p>\n\n\n\n<ul>\n<li><strong>Maintain Separate Versioned Classes<\/strong><\/li>\n<\/ul>\n\n\n\n<p>public interface IFeatureV1 { void Execute(); }<\/p>\n\n\n\n<p>public class FeatureV1 : IFeatureV1 { public void Execute() =&gt; Console.WriteLine(&#8220;Feature V1&#8221;); }<\/p>\n\n\n\n<p>public class FeatureV2 : IFeatureV1 { public void Execute() =&gt; Console.WriteLine(&#8220;Feature V2&#8221;); }<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Wrapping_Up\"><\/span>Wrapping Up<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>So, these are the top 30+ C# OOPs interview questions and answers to help you prepare effectively. Understanding these concepts will boost your confidence and improve your chances of success.Looking for <a href=\"https:\/\/www.hirist.tech\/k\/oops-jobs.html?ref=blog\" target=\"_blank\" rel=\"noreferrer noopener\">C# OOPs jobs<\/a> in India? Hirist is the perfect platform for tech professionals. Find top opportunities and take the next step in your career.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Are you preparing for a C# OOPs interview? Object-oriented programming (OOP) is at the core&hellip;<\/p>\n","protected":false},"author":1,"featured_media":6055,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22,29,19],"tags":[32,34,80,33],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Top 30+ C# OOPs Interview Questions and Answers (2026) - Hirist Blog<\/title>\n<meta name=\"description\" content=\"Looking for the most important C# OOPs interview questions? 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