What are the most frequently asked C# interview questions? How do I prepare for a C# developer interview?
Read on, and you’ll find the answers to these questions in this article.
First of all, C# is a general-purpose, modern, multi-paradigm, object-oriented programming language developed by Microsoft that runs on the .NET Framework. It is used to develop web, desktop, mobile apps, games, and much more.
In the following section, we have enlisted frequently asked ‘Advanced C# Interview Questions and Answers’ that will make you feel more confident in interviews!
Then, let’s take a look at the most frequently asked advanced C# interview questions and answers in technical interviews!
10+ Advanced C# Interview Questions and Answers
1. What is attribute in C#? What is it used for?
Attribute is a powerful feature that plays an important role within the C# ecosystem as it adds metadata information to your assemblies.
Moreover, attributes are used to convey declarative information or metadata about various code elements such as: Assembly, Class, Method, Delegate, Enum, Event, Field, Interface, Property and Struct.
You can add declarative tag information to a program by using an attribute. To define, a declarative tag is depicted by square ([ ]) brackets placed above the element it is used for.
A declarative tag is placed using square brackets ([ ]) on top of the required code element and added to the code.
For instance, the Microsoft .Net Framework provides two types of attributes: the pre-defined and custom built attributes.
Pre-define attributes: AttributeUsage, Conditional, Obsolete.
Custom attributes: The Microsoft .Net Framework allows creating custom attributes that can be used to store declarative information and can be retrieved at run-time.
2. What is the difference between reflection and dynamic?
Reflection is used for obtaining type information at runtime, and when managed code can read its own metadata to explore assemblies. Also, it allows code to check other code within the same system.
The dynamic keyword was introduced in .NET 4.0.
There are two types of programming languages: strongly typed and dynamically typed.
Similarly, both reflection and dynamic are used when we want to work on an object during runtime.
Reflection can invite both public and private members of an object, whereas dynamic can invite only public members.
On the other hand, dynamic is model specific, in which case you need to use reflection.
3. Explain the difference between ‘Task’ and ‘Thread’
Tasks are things you want to be done. It is a set of program instructions that are loaded in memory.
On the other hand, threads are basic units of CPU utilization, consisting of a program counter and a set of registers.
- Tasks are more abstract than arrays.
- A task may return a result. There is no direct mechanism to return the result from a thread.
- A task can have multiple processes at the same time. Threads can only have one task at a time.
- Task supports revocation through the use of revocation tokens, whereas thread does not.
4. What is encapsulation in C#? How is encapsulation implemented?
Encapsulation is one of the basic features of an object-oriented programming language.
Moreover, encapsulation is accomplished using access tokens.
C# supports the following access tokens:
- General: Access to all code
- Private: Access only to members of the same class
- Protected: Access to members of the same class and its derived classes
- Internal: Access to current assembly
- Protected Internal: Access to the current assembly and types derived from the containing class
5. What is a destructor in C#? When should I create a destructor?
One of the most frequently asked questions in the list of C# interview questions is about destructors!
First of all, destructors are the techniques to destruct instances of classes.
Clearing the cache and removing all instances are very advantageous techniques.
In C#, you can never call them –one can’t destroy an object.
By using destructors, you can release memory if your program is using expensive external resources such as files, images, etc.
Destructors also have several properties, which are the following:
- Destructors can be used only in classes
- A destructor can be symbolized by using the tilde (~) operator
- A destructor won’t accept any parameters and access modifiers
- The garbage collector automatically invokes the destructor whenever the class objects are no longer needed in the application.
6. What are synchronous and asynchronous operations?
Synchronization makes a thread-safe code where only one thread can access the resource at any given time and represents a set of activities that start happening together at a similar time.
Therefore, synchronous programming badly affects UI operations when the user tries to perform time-consuming operations as only one thread will be used.
On the other hand, asynchronous operation calls the method to complete before continuing with the program flow.
In this case, asynchronous programming allows a unit of work to run separately from the primary application thread.
It notifies the main subject when the job is complete and is a form of parallel programming.
7. Explain get and set accessor properties
Property provides a flexible mechanism for reading, writing, or calculating the value of a special field.
Moreover, properties are actually private methods called accessors. Therefore, they make data easily accessible and help to increase its flexibility.
The C# property has two accessors: get property and set property accessors. A get accessor returns a property value, whereas a set accessor sets a new value. Additionally, the value keyword represents the value of a property.
In C# 9 and later, the init property accessor is used only during object creation, for instance.
8. What are the types of serialization?
Serialization is converting an object into a data stream for storing or transmitting the object to memory or a database.
Mainly, its purpose is to save an object’s state so it can be recreated.
Contrast to this, the reverse operation is called deserialization. It provides the ability to transmit data over the network in a cross-platform compatible format and also save it.
For instance, serialization is used by Web Services SOAP, Remoting, to transmit data between a server and a client.
The opposite of serialization is the process of recreating the same object later.
Here are a few types of serialization:
- XML serialization: Serializes all public properties into XML document and is available in System.sml.Serialization.
- SOAP: Generates a complete SOAP-compliant envelope that can be used by any SOAP-aware system and is contained in System.Runtime.Serialization.
- Binary Serialization: Allows any code to be converted to its binary form. It’s fast and takes up little space.
9. What is a XSD file?
The XML Schema language is called XML Schema Definition (XSD) and defines the structure of the XML document.
It’s used to describe the possible structure and content of the XML format.
Additionally, during the Serialization of the C# code, the classes are converted to XSD compatible format by xsd.exe.
10. How to compile unsafe code?
To compile unsafe code, you must specify the /unsafe command-line switch with the command-line compiler.
For example, to compile a program called one.cs that contains unsafe code from the command line, issue the command: csc /unsafe one.cs
Follow the steps below.
Visual Studio IDE -> Enable unsafe code usage.
Open Solution Explorer -> Project properties.
Click the “Create” tab.
Select “Allow unsafe code”.
If you’re feeling ready for your C# interview, it’s time to meet a great job opportunity that’s right for you!
TalentGrid is a platform used by software developers who are actively looking for jobs, allowing them to share their preferences and salary expectations with tech companies worldwide.
By creating your TalentGrid developer profile, you’ll have an opportunity to be matched with tech roles all over the world!
