What is a .NET developer?

The .NET Framework is a powerful, adaptable software framework developed by Microsoft. .NET developers will handle the performance, testing, security and scalability of both web and mobile applications, and some developers will use the .NET Framework to develop websites as well as desktop and mobile applications. .NET developers seldom work in isolation and often coordinate with teams to more effectively build applications. 

These professionals typically have the following responsibilities:

• Collaborate with a team to develop web and mobile applications
• Translate app storyboards into functional applications
• Integrate data storage solutions
• Guarantee peak performance, quality and responsiveness of applications
• Identify bugs and other issues within applications, and develop solutions to address such problems
• Maintain code quality over time
• Design and develop clean and efficient code

Being a .NET developer combines creative problem-solving with technical coding and development that can improve companies and serve clients’ needs. Frequently required skills include:

• Proficiency in VB.NET or C# languages, or both
• Knowledge of the .NET Framework, down to particular versions
• Familiarity with Mono (if necessary)
• Collaborative skills
• Ability to write reusable libraries
• Understanding of object-oriented programming
• Familiarity with a range of design and architectural patterns
• Familiarity with Microsoft SQL
• Knowledge of concurrency patterns
• Ability to write clean and easily maintainable code
• Understanding of the strengths and limitations of Common Language Runtime
• Familiarity with Windows Presentation Framework
• Knowledge of popular web application frameworks
• Knowledge of the fundamental design principles required to develop a scalable application
• Experience building database schemas

Common .NET interview questions and answers

In preparation for your upcoming developer interview, here are common .NET interview questions that test your knowledge of the framework and the answers that will improve your chances of getting that job:

1. What is the .NET Framework?
2. What languages does the .NET Framework support?
3. What are the most important aspects of .NET?
4. What is the difference between managed and unmanaged code?
5. Explain in basic terms how to execute managed code.
6. Describe the garbage collection process.

1. What is the .NET Framework?

This is a common way for interviewers to start an interview for a software developer who needs to specialize in the .NET Framework. Show the interviewer your ability to utilize the .NET Framework effectively by describing what it is, when to use it and its main features. Try to show your practical knowledge of the system.

Example: “.NET is a Microsoft framework designed to help developers work with different coding languages. In simple terms, it’s a virtual machine that assists with the compilation, conversion and execution of code within a development framework. Using .NET, developers can create form- and web-based applications and services.”

2. What languages does the .NET Framework support?

Answering this question shows you have the basic knowledge and skills required to fulfill the needs of the position. The right candidate should be a knowledgeable programmer who is comfortable coding within the .NET Framework. In addition to telling what languages the framework supports, you can also provide your experience programming within those languages.

Example: “The .NET Framework supports more than 60 languages. This includes both Microsoft and non-Microsoft languages. The most common languages are VB.NET, Cobol, Perl, C#, C++ and F# languages.

I began my programming career by learning C#. It’s provided an important foundation for my professional development as a programmer. When I got my C# programming certificate, I was promoted to a full-time developer at National Telecom Ltd. In that role, I also learned F# and Cobol. This makes me very familiar with these common languages applied to the .NET Framework.”

3. What are the most important aspects of .NET?

.NET is an infrastructure that consists of multiple features like application domain, a common type system and profiling. Isolating one or two important pieces may be a challenge, but the interviewer may be looking for the answers “class library” and “Common Language Runtime.” It’s critical to make a case for why those are the most essential features. This is an opportunity to show your skills go beyond just technical because you can also apply critical thinking.

Example: “Common Language Runtime and Class library are the most important aspects of the .NET Framework. CLR provides building tools and resources that help developers set the foundation for application building. The class library holds essential classes used for providing commonly known functionality that is shareable across applications.”

4. What is the difference between managed and unmanaged code?

When developers work within an established framework, they should be aware of certain nuances, especially those between managed and unmanaged code. This question allows you to display your knowledge of working within the framework and to differentiate that knowledge from working in other coding environments.

Answering this question tests the depths of your programming knowledge and lets the interviewer know you are skilled enough to handle the various environments in the enterprise development lifecycle.

Example: “Managed code is managed by and runs inside the CLR and needs the .NET Framework to execute. Unmanaged code, on the other hand, does not need the CLR to execute. Unmanaged code is formulated from a language independent of the .NET Framework and therefore uses its independent environment for execution and compiling.”

Other questions an interviewer could ask to make sure you understand nuanced features of .NET include:

• Explain the difference between function and stored procedure.
• What are the different types of assemblies?
• What are the elements of an assembly?
• What are the two types of cookies in ASP.NET?

5. Explain in basic terms how to execute managed code.

Executing code is an essential function of any developer, but knowledge of executing managed code is specific to the .NET Framework. Your answer should explain how to execute code that runs inside the common language runtime environment the framework provides.

Additionally, whenever an interviewer asks you to explain something in “basic terms,” it’s important to pay attention to the language you use to make it as clear as possible. These types of questions are often asked when the position requires the candidate to be both very technical and also a good communicator who can explain their work to a broad audience. In some organizations, a lead developer may be responsible for reporting progress on an application to stakeholders. During these exchanges, they should be able to break down their work without using technical jargon or overly complicated language.

Example: “First, I would write the code. Then I would compile the code with a resource called a compiler. Using the compiler, I would convert the managed code into an intermediate language. The intermediate language will be targeted by the Common Language Runtime within .NET Framework and converted to native code that can then be executed inside the framework.

In my previous role as a developer, I was tasked with speeding up application delivery times. Using .NET and this process for executing managed code, I was able to reduce delivery timelines by 5% overall.”

6. Describe the garbage collection process.

Garbage collection is an essential process of the .NET Framework that performs memory usage optimization to allow for greater effectiveness of the platform. Answering this question allows you to show you’re an expert on the subject of .NET. It demonstrates knowledge of the framework that goes beyond just repeating theoretical concepts.