CodeSubmit Interview Series

10 Best .NET Interview Questions and Answers (2023)

Hiring a .NET developer? Then, you need the right .NET interview questions. Today, you get the best questions to ask your candidates. Read on! 

.NET interviews 

.NET (dotnet) is an open-source, cross-platform developer platform for building different types of applications. It can be used together with many languages, editors, and libraries to build for the web and mobile. 

If you’re in the process to hire .NET developers, you need .NET interview questions to assess your candidates. Here below are some of our top picks (we’ve spent years in technical recruitment and are well-versed in what makes good interview questions). 

Interviewing developers isn’t always easy. That’s why you need the right interview questions. And if you’re looking to assess their technical skills in a reliable and flexible way, take a look at our .NET coding challenges.

Beginner .NET interview questions

What are the best .NET interview questions for junior developers? Here are our top picks. 

None of these are questions that need to be answered word for word. Instead, look deeper to understand the candidate’s experience and understanding of .NET. 

1. What is the .NET framework simply explained? 

Answer:

Let’s start with the fundamentals. It’s always a good idea to ask candidates to define the language/framework you’re interviewing for to understand what their scope of knowledge is. Naturally, junior developers won’t likely have a deep knowledge of the framework, but you gauge their level. 

.NET is a cross-platform and open-source software framework developed by Microsoft. It’s used for building different types of applications and it can be used with different languages, libraries, and editors to build web and mobile applications.

2. How does .NET work? 

Answer: 

This question digs a bit deeper into the way .NET works.

.NET includes a large class library, which is called Framework Class Library (FCL). It enables several programming languages to use code written in other languages. Programs written for .NET are executed in a software environment instead of a hardware environment, which is called the Common Language Runtime (CLR). FCL and CLR are the two main components of the .NET Framework. 

Applications based on the .NET framework and that are written in supportive languages like C# and F# are compiled to Common Intermediate Language (CIL). 

When .NET is running, CLR takes this file and converts CIL into code with the help of Just In Time (JIT). 

Code that is written in .NET is called managed code. 

3. What is assembly? 

Answer:

Assembly is a file that the compiler automatically generates. It consists of a collection of types that work together and form a logical unit. Assembly files are stored as .exe (executable) or .dll (dynamic link library) files. 

4. What’s your experience with .NET? Tell me about a recent project you worked on.

Answer: 

This question lets you dig deeper into a project and ask specific, technical questions about that project. If you need/want to, probe with questions like, “What happened next?”, “Why did you decide to do X?”

Advanced .NET interview questions 

Need .NET interview questions for experienced professionals? Here are questions to ask to get a better understanding of candidates’ understanding of .NET. 

5. What are ASP.NET security controls? 

Answer:

.NET developers who understand ASP.NET security will be able to build secure applications. You might want to follow up with a few questions to see how candidates have used these security controls in their own, daily work. 

  • <asp: Login> Login capability that lets users enter their credentials 
  • <asp: LoginName> You can display the name of the user who is logged in
  • <asp: LoginStatus> Shows if the user is authenticated or not
  • <asp: LoginView> You can see various login views, depending on the template
  • <asp: PasswordRecovery> Emails lost passwords to users  

6. What are the different types of constructors in C#? 

Answer: 

C# has 5 types of constructors. These are: 

  • Default constructor: without any parameters
  • Copy constructor: copies variables from another object to create an object
  • Static constructor: it’s created using a static keyword and it will be invoked once for all of the instances of the class
  • Parameterized constructor: it has one parameter
  • Private constructor: it’s created with a private specifier and it doesn’t allow other classes to derive from it or create an instance 

7. What is the difference between constants and read-only variables? 

Answer:

Constants and read-only variables are similar in many ways. But there are some important differences.

  • Constants support only value-type variables (and strings). Read-only variables hold reference-type variables.
  • Constants are evaluated at compile time. Read-only variables are evaluated at run-time. 
  • Read-only variables can only be initialized at declaration or in a constructor. 
  • Constants can be used when the value isn’t changing during run time. Read-only variables are used mainly when their actual value isn’t known before run time.

8. What is multithreading? 

Answer:

Multithreading, which is supported by .NET, is a process that includes multiple threads, with each of them performing different activities in a single process. .NET supports multithreading in these ways:

  • Threads started with ThreadStart delegates
  • Using the ThreadPool class with an asynchronous method 

9. What is the garbage collection process?

Answer:

The garbage collection process is an important process with the goal to make the platform more effective. 

The garbage collector process is used to release unused code that’s lying in the memory. It releases code at different times for three different generations that are divided in the memory. Generation 0 (which is short-lived) has frequent garbage collector releases, whereas Generations 1 and 2 are released more seldom. 

First, the garbage collector identifies a list of live objects. It then updates the references for the objects the collector will compact. Last, the collector reclaims the space that was taken up by dead code. The code that remains will now be taken to an older segment. 

Assess .NET developers 

There you have it! These are the top .NET interview questions.

But once you have your interviews set up, how do you assess developers’ skills? Try our coding challenges! 

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And for more Interview Question Examples, check out our blog!