C# Interview Questions

C# Interview Questions

Among the many available programming languages, C# is a simple, object-oriented, and multi-purpose tool that was developed by the famous Microsoft. C # has a unique feature in that it supports the NET initiative, which allows you to create interactive websites, web applications, video games, and more. And since you can build so many things using your C# knowledge, you can learn the programming language to develop a career in the field. With career opportunities comes the necessity of interviews, and to prepare yourself for them, you need to study. Here are some basic and tricky C# interview questions to start preparing yourself in 2021.

C# Basic Questions of Interviewees

The C# language is in high demand for a variety of reasons. First and foremost, it is based on C, the most basic of all computer languages. Second, it is less difficult to learn than other programming languages like Java, Python, and others. You may use C# to create video games, web apps, and websites, among other things. It also offers interfaces, trash collection, and a variety of other features that aid in the development of better applications. That is why, in order to advance your profession, we recommend that you study C#. To begin, below are some of the most frequently asked fundamental interview questions.

1. How Do You Think C# and C Are Distinct From One Another?

C is the first programming language that Microsoft ever developed and C# is the second one in the series. C# is an object-oriented language that supports automatic garbage collection but C doesn’t. C# needs a .NET framework to work but C is known as a platform-agnostic language. C programming language works more on functions but C# works on design, C gives an overall great performance in the application development but C# gives an objective-oriented performance.

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2. What Do You Mean By Common Language Runtime (CLR)?

CLR is a basic VM element that runs code, provides remoting, type-safety, thread management, and other features, similar to the.NET Framework.CLR is the name of the technical environment of the.NET Framework that controls the implementation of.NET components regardless of programming language. It also manages the codes, and that code will be known as “Managed Code” in the CLR. Code that does not target runtime is known as “unmanaged” code.

3. What is an Object in C#?

In the C# programming language, an object is a type of class that allows you to access the class’s methods. You can use the keyword “new” to produce an object, and the class that creates the object in memory will provide you with information about variables, methods, nature, and other aspects of that class.

4. What is the Garbage Collection?

Garbage collection is a component in .NET Framework that makes Automatic memory management easier. Some memory space will be assigned to a class object once you create it in the runtime. You cannot use the memory space assigned to the object in other cases especially when the action allocated to the object is over. But with garbage collection, the class can release the memory space after the action is over. Garbage collection mostly works on the Managed Heap and also has an engine that we call Optimization Engine. The garbage collection will take place in cases of a few terms. If your computer has a low system memory, garbage collection is essential. If the pre-set limit of the memory space assigned to different objects is crossed, then garbage collection will take place.

5. What Are the Different Classes in C#?

The different classes in C# are Abstract class, Static class, Partial Class, and Sealed class.

C# Advanced Interview Questions

If you are familiar with the basic questions of C# that you might be asked during an interview, then the next step you should take is to memorise some advanced interview questions regarding C#.

6. What are Managed and Unmanaged Codes?

You can run managed codes on the CLR runtime environment in a .NET framework and the codes can be run on the managed runtime environment without the operating system. These codes usually provide garbage collectors, exception handling, etc. Unmanaged codes, on the other hand, are codes that don’t run on the CLR and also work outside of the.NET framework. These codes don’t offer services that consist of high-level languages, and that’s why you can run unmanaged codes without high-level programming languages. You can run unmanaged codes with C++.

7. What is the Contrast Among ref and Out Keywords?

In C#, the ref keywords use arguments by references and not the values of the keywords. So, if you want to use the ref keyword, you need to mention “ref” intentionally.

void Method(ref int refArgument)


refArgument = refArgument + 10;


int number = 1;

Method(ref number);


// Output: 11

In C#, Out keywords use arguments within the method and function. The “Out” keyword passes arguments in the references to return different values. Out is the same as a ref, but the ref needs to be initialized before you pass it on. Here is an example:

public static string GetNextFeature(ref int id)


string returnText = “Next-” + id.ToString();

id += 1;

return returnText;


public static string GetNextFeature(out int id)


id = 1;

string returnText = “Next-” + id.ToString();

return returnText;


8. What is the Difference Between Public, Static, and Void?

You can find public declared methods or variables within the application. Static declared variables, on the other hand, do not require the creation of a class in order to be globally accessible. If the static variables are not globally accessible, the type of access utilized determines this. The method’s address will be saved in the compiler as its entry point, and the static decorations will be used to start the execution even before any objects in the program are produced. If a Void exists, it is a type modifier that specifies a method or variable even if it does not return a specific value.

9. Describe Custom Control and User Control

Controls created as compiled code (Dlls) are known as Custom Controls that you can easily use and add to the toolbox. You can drag and drop controls onto the web forms and can design the attributes at any time. You can also add custom controls to different applications if they are shared DLLs. But if the Dlls are private, you can copy the dll to the bin directory of the web apps. You can also add references and apply them whenever you want. User controls are also somewhat like ASP include files and these files are easy to generate. You can keep the controls in the toolbox and drag and drop them wherever you want. These user controls have their own designs and codes and their extension is ascx.

10. What is Reflection in C#?

Reflection in C# uses metadata from its data types when you are running them within the runtime. To determine the data type, use the System Reflection namespace, which can be Assembly, MethodInfo, Module, ConstructorInfo, Enum, ParameterInfo, Type, MemberInfo, FieldInfo, PropertyInfo, or event info.

11. What do you Mean by Method Overloading?

Method overloading refers to building different methods that will have the same name, same class, but different and new signatures. If you compile the methods, you will have to use overload resolution to identify the specific method that you need guidance with.

12. How Do You Differentiate Array and Arraylist?

You can have the same types of items in the array, but the size of the array will also be a fixed number when you compare it to an ArrayList. An ArrayList is also similar to an array but does not include a firm size.

13. Tell Something About Generics in C#.NET

Generics can reduce code redundancy, and boost performance, safety, etc. Developers use generics to create reusable code classes and collection classes, generic collection systems, etc.

14. How Do You Implement Singleton Design Pattern in C#?

A class will have only one instance and a global access point. For example, Public sealed class Singleton


Private static readonly Singleton _instance = new Singleton();


15. Tell us Something about the Indexers in C# .NET

Indexers, also known as smart arrays, allow a class instance to be indexed like an array. For example, public int this[int index] // Indexer declaration

16. How do you use Nullable Types in .Net?

The value types won’t take normal values or null values, and those types are known as nullable types in .Net. such as Int? someID = null;


17. How to Catch an Exception in C#?

Use try-catch blocks with the system. Exception type or parameters for example: try {



catch (Exception ex) {


18. Why Should you Learn C#?

C# is easy to learn, it is a general-purpose and object-oriented language, and a part of the net framework. It is also easily complied with on different system platforms.

19. How to Specify a Property in a class

int m_PersonID = 0;

public int PersonID


get { return m_PersonID; }

set { m_PersonID = value; }


20. What are the Best Access Modifiers in C#?

The access modifiers in C# are Public, Private, Protected, Internal, and Protected internal.


You can study these common questions for the starters, and your C# interview will go well. But if you want to increase your chance of getting selected, then you need to study more C# Interview Questions from both advanced and beginner levels. For starters, there can be MCQ-type questions in your C# interview. Questions like “What are the types of ‘Data Conversion’ in C#?” are also common during C# interviews. So, make your best preparation and follow our other guides if you need to. Best of luck!

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