In this guide, we discuss the top 100 critical interview questions to ask .NET developers as an interviewer. We’ll give the standard answer to each of them with examples where necessary. As a bonus, we also discuss some important tips to help you prepare to interview .NET developers in the current job market.
Overview of .NET
By numbers, Microsoft’s .NET is one of the biggest software development technologies used in all industries and markets worldwide. Naturally, it is very popular in enterprise software development as Microsoft is the leading OS platform for businesses globally. Today, large and influential companies like JP Morgan Chase, Cisco, Coca-Cola Samsung, and Intel, use it to build or maintain existing applications.
Because .NET is so large, professionals who use it tend to prepare themselves for a job in a myriad of roles including .NET solutions development, web development with ASP.NET, cloud development with .NET, etc. You can, therefore, expect to find some of the most talented professionals in the market if you are hiring for any developer-related positions.
Importance of Interview Preparation for Interviewers
Like most people, you might be tempted to rely on your knowledge and skills when interviewing .NET candidates if you are an experienced developer. Maybe you have held various senior developer positions or have been developing .NET solutions for years. Here are some of the reasons we think you should prepare as an interviewer regardless of your experience level:
The entire .NET platform is so large. There are so many components and concepts in .NET that it’s not practical for you to have learned everything through experience. You need to understand how .NET developer interviews are structured in order to ask the right questions and gauge candidate competence.
Secondly, dotNET interviews should be designed to reveal a candidate’s depth of understanding of .NET. For this reason, you might find yourself struggling to link what you know through practice and the questions you need to ask. This is why there are so many resources online aimed at preparing interviewers for technical interviews.
With the above at the back of your mind, we advise that you look beyond the skills, knowledge, and experience you have as an interviewer and prepare for the interview as an isolated exercise. Reading this guide is part of your preparation as you’ll get an inside look at the interview questions to ask .NET developers and example answers.
Top 100 .Net Interview Questions and Answers for A .NET Developer
The following questions are very common in .NET developer interviews. Where necessary, we explain why they are asked and suggest an answer you might give for each. Let’s right into it!
1. What Is .Net And What Are Its Main Components?
To lay a foundation and gauge the depth of candidate’s knowledge right away, you can ask the candidate to describe .NET and its main components. Providing a strong well-thought-out answer demonstrates that they understand .NET beyond the basics and can use it to develop applications.
A possible answer to this question is that .NET is a technology by Microsoft providing a managed runtime environment, libraries, and APIs for developing and running applications. The main components of .NET include the Common Language Runtime  (CLR), Framework Class Library (FCL), and programming languages like C#. dotNET is used to develop all kinds of applications including desktop applications, mobile applications, and web applications.
2. Explain the Difference Between Managed and Unmanaged Code In .NET
Managed code is where raw code is compiled and executed in a controlled environment which is the Common Language Runtime (CLR) in dotNET. On the other hand, unmanaged code is compiled or translated directly into machine code for execution.
3. What Is the Common Language Runtime (CLR)?
Unless you are interviewing for a senior .NET developer position and have years of experience, you will be asked to explain the Common Language Runtime. The CLR is a vital component of .NET which manages the execution of code. The CLR also provides other services in the managed code execution environment such as memory management, exception handling, and security.
4. What Is the Global Assembly Cache (GAC)?
This is a common question in most .NET framework interviews as it involves the storage of assemblies which affects how applications execute. The Global Assembly Cache (GAC) is a systemwide store for assembly cache present in all systems where the Common Language Runtime is installed. The GAC provides assembly cache access to all installed .NET applications.
5. What Is the Role of The JIT (Just-In-Time) Compiler In .NET?
The Just-In-Time compiler, simply referred to as JIT, converts Common Intermediate Language code into machine code during execution or runtime. The use of the JIT allows any application written in .NET to be language and platform-agnostic as there is no need for precompiled binaries.
6. Explain the Concept of Garbage Collection In .NET
Garbage collection is a function of the Common Language Runtime whereby memory is automatically freed up as soon as it is not needed by a running .NET application. Automatic garbage collection in the CLR improves efficiency during runtime. Garbage collection also frees developers from manual memory usage allocation and deallocation.
7. What Is the Difference Between Value Types and Reference Types In .NET?
In .NET, value types store a direct value in a stack while reference types only indicate or store a reference to a value on a heap. Reference types are what traditional programmers could refer to as pointers. An example of a simple value type in .NET Is an Integer (Int) and a common reference type could be an array for example.
8. What Is an Abstract Class In .NET?
An abstract class in .NET is one created to be a base class for other classes and is therefore never instantiated. In most cases, abstract classes contain abstract functions or methods that one can implement in a derived class somewhere in their code. Abstract classes are useful in .NET as they allow the developer to reuse or extend common functionality in their applications.
9. What Is an Interface In .NET And How Is It Different from A Class?
An interface in .NET can be defined as a contract pre-specifying some properties and functions or methods that must be implemented by a class. Interfaces are used to define or specify a standard communication protocol for objects in a .NET program.
10. What Is the Difference Between an Abstract Class And An Interface In .NET?
The main difference between an interface and an abstract class in .NET is that an interface specifies methods and properties that a class must implement while an abstract class can contain details to be implemented in a derived class. These two constructs serve different purposes and are equally important in a .NET project.
11. What Is A Delegate In .NET?
Delegate types in .NET are references for methods or functions. Using delegate types, a developer can pass a function or method as a parameter to another method. .NET developers normally use delegate constructs to implement event handling where it is required. A delegate is a unique construct in .NET.
12. What Is an Event In .NET And How Is It Different from A Delegate?
Events as viewed from a .NET perspective are mechanisms or constructs used to notify other code when something is taking place that should trigger an action or needs to be watched. Events in .NET are based on delegate constructs in .NET but they offer programmers more control over event management.
13. What Is A LINQ (Language Integrated Query) And How Does It Work?
Language Integrated Query (LINQ) is a unique technology in .NET that allows developers to write queries using standard programming language syntax. LINQ is primarily used to query data from different data sources without the need to write SQL code or other data source-specific query language. Â You can use LINQ to query databases, collections, XML files, etc.
14. What is .NET Core?
.NET Core is modern open-source, cross-platform used to build modern applications that run on Windows, the web and other platforms. It is the modern version of .NET and the current version is .NET 7. dotNET Core is managed by the .NET foundation.
15. What is the main Difference Between .NET Core and the .NET Framework?
The main difference is that .NET Core is cross-platform while the .NET Framework is Windows-only which means it only runs in Windows systems.
16. What Is the Advantage of Using .NET Core Over The .NET Framework?
By design .NET Core is said to offer improved performance, scalability and flexibility due to the ability to target multiple platforms, including Windows, Linux, and macOS.
17. Explain the Concept of Cross-Platform Development In .NET Core
Cross-platform development refers to the idea of writing code once and running it on different operating systems and platforms, such as Windows, Linux, macOS and mobile. .NET Core applications are cross-platform by design.
18. How Does Dependency Injection Work In .NET Core?
Dependency injection in .NET Core enables developers to decouple various components in their applications and manage their dependencies. This practice makes their code more maintainable and testable.
19. What Is Middleware in ASP.NET Core?
In ASP.NET Core, middleware refers to a pipeline that processes HTTP requests and responses, enabling developers to add functionality. Such functionality may include authentication, logging, or exception handling.
20. Explain the concept of Tag Helpers in ASP.NET Core.
In ASP.NET Core, Tag Helpers provide developers a way to generate HTML dynamically and declaratively. This simplifies the process of creating views in .NET Core MVC applications.
21. What Is the Role of The Startup Class in ASP.NET Core?
The Startup class is responsible for configuring an application’s services and middleware. It may include things like setting up dependency injection or defining the request handling pipeline.
22. How Do You Configure Routing in ASP.NET Core?
Routing determines how incoming HTTP requests are matched to specific actions or endpoints a web application created with ASP.NET Core. This allows developers to define custom URL patterns as well as route parameters.
23. What Are the Different Types of Caching in ASP.NET Core?
In ASP.NET Core, caching enables developers to store frequently accessed data in memory or a distributed cache. Implementing caching reduces response time thus improving application perfomance and responsiveness. Â Caching can be implemented in various ways in ASP.NET Core applications and it is recommended as a best practice.
24. What Is ASP.NET And What Are Its Main Components?
ASP.NET is the web development framework included in .NET. You can find all the important components needed to build modern web applications in a managed coding environment. ASP.NET makes it easier and faster to build both simple and complex web applications that are designed to be highly scalable and dependable.
25. What is MVC (Model-View-Controller) architecture and how is it used in ASP.NET?
The MVC in .NET is a standard design pattern you can use to build complex ASP.NET web applications from the ground up. MVC web applications are made of a model, a view, and a controller, hence the name MVC.
The model contains the code defining and referencing application data and the business logic. The “view†contains code defining the user interface or front end of the web application. The controller contains code that deals with user input, data access, and manipulation.
26. What is Entity Framework and how is it used in .NET applications?
In .NET, the entity framework is the mapping framework that a developer uses to work with databases with standard programming language syntax and constructs in the form of objects. The object-relational mapping framework includes special Application Programming Interfaces (APIs) a programmer can use to query and update databases in their code.
27. What is WCF (Windows Communication Foundation)?
Windows Communication Foundation (WCF) is a sub-framework within .NET that developers can use to build distributed application functionality. For instance, a developer can add network-based communication in their .NET application using the APIs and pre-built libraries in WCF. It is one of the major sub-frameworks in .NET used to build complex business applications.
28. What is a web service in .NET?
In .NET, a web service is a system or mechanism a developer can use to implement interoperable machine-to-machine interaction. The machine-to-machine interaction is done over a network using standard web protocols like HTTP and SOAP or over a network using TCP/IP.
29. What is REST (Representational State Transfer) IN .NET?
Representation State Transfer (REST) in .NET is a web architecture that facilitates communication between servers and clients using standard HTTP methods like GET and POST. REST APIs are supported in .NET and are heavily used in client-server and server-based web applications.
30. What is SOAP (Simple Object Access Protocol) and how is it used in .NET applications?
SOAP is a protocol used to exchange structured data over the internet in ASP.NET applications. SOAP utilized XML and supports many communication protocols such as document-style messages and RPC-style calls inside ASP.NET applications.
31. What is ADO.NET and how is it used in .NET applications?
ADO.NET is one of the main data manipulation components inside .NET. Developers use ADO.NET to programmatically access and manipulate database data (relational data). ADO includes a set of APIs and pre-built classes to make it easier to work with databases inside .NET applications. You can build and execute normal SQL queries inside your .NET application with ADO.NET.
32. What is the difference between LINQ to SQL and Entity Framework?
LINQ is used to access database data using standard programming language syntax in .NET applications. The Entity Framework is a general-purpose object-relational mapping framework used to work with different types of database systems inside .NET applications.
33. Explain the Concept of Asynchronous Programming In .NET.
Asynchronous programming in .NET refers to the programming paradigm used for concurrent task execution. Developers use Async methods and the “wait†keyword to implement asynchronous programming in .NET applications.
34. What Is the Difference Between A Thread and A Task In .NET?
In .NET, a thread can be a simple or singular unit of execution running concurrently with other processes. Tasks, on the other hand, are units of work executed asynchronously. In .NET a task can be executed on a thread which itself is part of a pool.
35. What Is Nuget And How Is It Used In .NET Applications?
Nuget is the universal package manager inside .NET. Developers use Nuget to install and manage third-party libraries or dependencies they need in their applications. The third-party libraries or dependencies are called Nuget packages in .NET. The Nuget package manager is integrated into the Visual Studio IDE.
36. What Is the Difference Between SqlCommand And SqlDataAdapter In ADO.NET?
In .NET the SqlCommand keyword is used to run an SQL command on an underlying database. SqlDataAdapter keyword on the other hand is used to retrieve data and populate underlying database dataTable objects or dataSet objects.
37. What Is the Difference Between SqlDataReader And Dataset In ADO.NET?
The SqlDataReader keyword in ADO.NET enables you to read database data in an SQL database fast and forward-only manager inside your .NET application. Using the DataSet keyword allows you to create an in-memory cache of retrieved database data for manipulation and updating.
38. How Do You Handle Errors and Exceptions in ASP.NET Core?
In ASP.NET Core, error handling and exception handling entails capturing and processing exceptions that usually occur during application execution. This allows developers to handle and log errors in a graceful and secure manner for the best user experiences. It prevents applications crashing or throwing cryptic errors in production.
39. Explain the Concept of Razor Pages in ASP.NET Core.
Razor Pages provide a page-based programming model that is simple and aligned to modern web development best practices. Developers can use razor pages to define both the UI and the behavior of a web application in a single file.
40. What Is the Difference Between ASP.NET Core MVC And ASP.NET Core Web API?
Developers use ASP.NET Core MVC to build web applications with a Model-View-Controller pattern. On the other hand, ASP.NET Core Web API is used to build HTTP-based APIs which are consumed by clients.
41. How Do You Perform Unit Testing In .NET Core?
Unit testing in .NET Core involves writing automated tests to gauge the correctness of individual units of code. This helps ensures that an application functions as expected before it is put into production.
42. What Are the Advantages of Using Entity Framework Core Over Entity Framework 6?
The Entity Framework Core is a lightweight, cross-platform version of Entity Framework. It has improved performance, additional features, and has better compatibility with modern database systems. It is still the same familiar Entity framework that has been part of .NET for years but with improvements.
43. Explain the Code-First Approach in Entity Framework Core
The code-first approach in Entity Framework Core allows developers to define a domain model using code and then generate the corresponding database schema automatically.
44. What Is A Migration in Entity Framework Core?
Migrations in Entity Framework Core are principally used to manage changes to database schema over a set time period. This functionality allows developers to update databases without losing existing data.
45. How Do You Handle Database Transactions In .NET Core?
In .NET Core, developers can handle database transactions using the TransactionScope class or explicit transaction management functions provided by the database provider.
46. What is the purpose of the appsettings.json file in ASP.NET Core?
In ASP.NET Core, the appsettings.json file Core is mainly used to store configuration settings for an application, such as database connection strings, API keys, or logging settings.
47. How Do You Secure an ASP.NET Core Application?
Securing an ASP.NET Core application or service mainly involves implementing authentication, authorization, and using secure communication protocols. This is done to  protect sensitive data and prevent unauthorized access to application data and protected functionality.
48. What Is A Data Adapter in ADO.NET And How Is It Used?
Data adapters in .NET are used as bridges between datasets and their sources. You can use the data adapter to retrieve database data and populate datasets with the retrieved data. It can also be used to update the underlying database based on the changes made to the dataset.
49. What Is A Data Reader in ADO.NET And How Is It Used?
In the context of ADO.NET, a data reader provides forward-only data streams from an underlying data source like a database. Data readers are primarily used where large amounts of database data need to be retrieved inside a .NET application. For instance, you can retrieve an entire table or multiple tables.
50. What Is A Dataset in ADO.NET And How Is It Used?
When you retrieve database data into your .NET application using ADO.NET it needs to be stored in a “surface-level†location for usage. The dataset feature allows the storage of retrieved database data in a memory cache.
51. What Is the Difference Between LINQ To SQL And LINQ To Entities?
LINQ to SQL allows .NET developers to programmatically map SQL database tables to objects. LINQ to entities is more advanced with additional mapping and querying features. The latter supports more databases and data sources and is used in complex data-driven .NET applications.
52. What Is A Lambda Expression In LINQ And How Is It Used?
Lambda applications are used in LINQ TO define projections, predicates, and transformations targeting database data. They provide a direct way of defining anonymous functions used across .NET applications including with LINQ.
53. What Is Iqueryable In LINQ And How Is It Used?
The IEnumerable type is used to represent a collection of enumerable objects inside .NET applications. It can e used to transform and filter data and datasets in LINQ. IEnumerable is also commonly sued to iterate over collections in .NET applications.
54. What Isiqueryable And How Is It Used In LINQ?
IQueryable represents queryable data sources in LINQ. You can use it to create queries in standard languages that are later converted into the appropriate query language of the data source you are accessing in your application.
55. What is Web API and how is it used in .NET?
In .NET, Web API is used to add HTTP services inside applications for communication over the Internet. You can use Web API in .NET to implement RESTful APIs and transmit all kinds of data and media types over the web.
56. What Is SignalR And How Is It Used In .NET?
SignalR is a core library in .NET that a developer can use to implement real-time functionality in their web applications. For instance, SignalR can be used in web applications to retrieve data in real time from a remote database.
57. Define the Code First Feature in The Entity Framework
The “code first†feature enables you to write database schema using standard code syntax. It is a fluent API for defining the mapping between classes and database stores or tables. You can also generate schema automatically when using the “code first†feature inside the entity framework.
58. Describe the Database-First feature in the Entity Framework
The “database first†feature is used to generate normal .NET classes from the selected database schema. You can use a visual designer to map data stores or database tables to your .NET classes with full support for inheritance and complex types. It is a useful feature for database-driven application development inside .NET.
59. Discuss the Model First Feature in the Entity Framework
In .NET Entity Framework, the “model first†feature allows you to create complex database schemas using the visual designer. The visual designer allows you to create tables, relationships, and other elements needed to create a database schema. The model is then mapped to a database in a round-trip engineering method.
60. What Is Dependency Injection In .NET?
In the context of .NET development, dependency injection refers to the design pattern used to promote loose coupling. Instead of creating dependencies directly in a component, it is injected into its properties or constructor which allows for easier testing and flexibility when it comes to refactoring.
61. Briefly Discuss Inversion Control In .NET
In the context of application development in .NET, inversion control refers to a design that promotes modular design and loose coupling. Instead of creating and managing objects directly in code, they are created in a separate framework or container.
62. Describe Unit Testing In .NET In A Sentence
In .NET, unit testing involves testing singular units of code in isolation by writing tests that invoke methods and classes to see if they are working as expected.
63. Describe Integration Testing In .NET In A Sentence
Integration testing in .NET involves developing and running tests to see the interaction of various components in a project to see if they are working together as expected.
64. Discuss What Mocking Means In .NET
Mocking in .NET is a testing technique that involves replacing real objects with simulated objects. The mocking technique allows the developer to isolate units of code for testing.
65. Briefly Discuss What Continuous Integration Means In .NET
Continuous integration in .NET application development is used to automate the build and test code as it is committed to the shared code repository. It is a seamless and real-time integration of code testing, feedback, and commitment to shared repositories.
66. Briefly Discuss What Continuous Delivery Means In .NET
In .NET projects, continuous delivery is the process of automating code deployment. Continuous delivery eliminates the need for manual intervention in building, testing, and deploying code to production systems.
67. What is JWT authentication in .NET Core?
JWT authentication involves issuing and validating JSON Web Tokens (JWTs) to authenticate and authorize users in .NET Core. Doing this enables a stateless and scalable authentication mechanism.
68. Explain the Concept of The Middleware Pipeline in ASP.NET Core
The middleware pipeline in ASP.NET Core enables developers to chain and configure multiple middleware components to process incoming HTTP requests and outgoing responses in a pre-determined order.
69. How Do You Handle Logging In .NET Core?
Logging in .NET Core enables developers to record and monitor events, exceptions, and other relevant information during the execution of an application. It helps with debugging and diagnostics.
70. What Is the Purpose of The ConfigureServices Method in The Startup Class?
The ConfigureServices method in the Startup class is used to configure and register services required by your application. This may include database contexts, authentication providers, or custom services. It uses the built-in dependency injection container.
71. What Are Health Checks In .NET Core?
Health checks allow developers to monitor application health and its dependencies, such as databases or external services. It also provides insights into an application’s overall status and availability.
72. How Can You Deploy A .NET Core Application?
Developers can deploy .NET Core applications using various methods. Examples include using self-contained deployment, containerization with Docker, or deploying to cloud platforms like Azure. Deployment can happen during testing but it is usually done when code is ready for deployment.
73. What Are Docker And Kubernetes In The Context Of .NET Core?
Docker is a platform that supports the packaging and distribution of applications as lightweight, portable containers. Kubernetes is a container orchestration system which is used to automate deployment, scaling, and management of containerized applications in .NET Core.
74. How Can You Manage Configuration Settings In .NET Core?
Developers can manage configuration settings in .NET Core using various sources, such as JSON files, environment variables, command-line arguments, or Azure Key Vault. This allows flexible and centralized configuration management.
75. What Is Hosting In .NET Core?
In .NET Core hosting refers to the process of running an application on a server or platform. Servers provide the necessary infrastructure and runtime environment for the application to execute and be accessible from more than one location. Â For instance, organizations put their web applications on web servers so they can be accessible from multiple devices.
76. How Do You Handle Background Tasks In .NET Core?
Background tasks in .NET Core allow devs to perform long-running or scheduled operations asynchronously. This may include things like sending emails, processing queues, or generating reports without blocking the main application thread in an application.
77. What Is Azure and How Is It Used In .NET?
Azure is not a part of the .NET software development framework. It is a cloud computing platform that can be used to build and deploy cloud-based .NET applications. Azure provides virtual machines, storage, networking, databases, and other components needed to build and run .NET applications in the cloud.
78. What Is the Difference Between Synchronous and Asynchronous Programming In .NET Core?
In .NET Core Synchronous programming executes code sequentially thus blocking the execution until the current operation is completed. On the contrary, asynchronous programming allows concurrent execution, improving responsiveness and scalability.
79. How Do You Handle Concurrency in Entity Framework Core?
Concurrency in Entity Framework Core involves managing simultaneous database access. This ensures data integrity, and handling of scenarios where multiple users or processes try to modify the same data at the same time.
80. What Is the Purpose of The IWebHostEnvironment Interface in .NET Core?
The IWebHostEnvironment interface provides information about the web hosting environment. This may include things like the application’s content root path, environment name, or configuration settings specific to an environment.
81. What Is Cross-Origin Resource Sharing (CORS) In ASP.NET Core?
Cross-origin resource sharing (CORS) in ASP.NET Core enables devs to to specify which domains are allowed to make requests to an application. This ensures requests from other domains are handled securely.
82. What Is the Purpose of Configuration Settings In .NET Core?
Configuration settings in .NET Core allows developers to customize and control the behavior of an application. It may include database connection strings, logging levels, or feature toggles.
83. What is the IHostedService Interface in .NET Core?
The IHostedService interface in .NET Core can be used to define background tasks or services that are managed by the application’s host and started automatically on application launch.
84. How Do You Handle File Uploads in ASP.NET Core?
File uploads in ASP.NET Core are handled by configuring appropriate form data processing, validating file types and sizes, and saving the uploaded files to a specified storage provider or a custom location.
85. What Is the Role of The IApplicationBuilder interface in ASP.NET Core?
The IApplicationBuilder interface in ASP.NET Core can be used to build the request processing pipeline. It involves adding middleware components, defining routing rules, and configuring exception handling and static file serving.
86. How Can You Implement Caching in ASP.NET Core?
Caching can be implemented using built-in caching middleware. Alternatively, developers can create a custom cache service. For instance, a developer can choose to use the Response Caching middleware to cache HTTP responses based on the request URL or headers. Thy can also create a distributed cache service using a caching provider like Redis to store frequently accessed data.
87. What Is the Purpose of The Appsettings.Development.Json File in ASP.NET Core?
The appsettings.Development.json file in ASP.NET Core is principally used to store configuration settings applicable only in the development environment. This allows different configurations for different environments.
88. Explain How Docker Can Be Used In .NET
Docker is one of the supported containerization platforms in dotNET. It can be used to package and deploy applications in self-contained units that are portable and lightweight. Â For .NET development, Docker provides an efficient way to deploy large applications in multiple environments, operating systems, and architectures.
89. Discuss Blazor and its role in .NET development
Blazor is one of the web development frameworks inside .NET Core. It is used to build modern web applications using WebAssembly and C# instead of JavaScript. Blazor web applications run on the user’s browser which makes them fast and more responsive than server-based web applications.
90. What Is Data Seeding in Entity Framework Core?
Data seeding in Entity Framework Core involves populating the database with initial data during application startup, enabling you to pre-configure data required for the application to function correctly.
91. What Is the Difference Between Authentication and Authorization in ASP.NET Core?
Authentication in ASP.NET Core involves verifying user identities. On the other hand, authorization involves determining the access rights and permissions of authenticated users and controlling what actions they can perform.
92. What Are the Different Types of Testing In .NET Core?
Testing in .NET Core can be unit testing, integration testing to test interactions between components, and load testing to assess the performance and scalability of the application in different scenarios. All these test types are important in .NET Core development.
93. What Is Concurrency in ASP.NET Core?
Concurrency in ASP.NET Core is the handling of situations where multiple requests are being processed simultaneously. This ensures data consistency and avoidance of race conditions or deadlocks.
94. What Are Razor Class Libraries (RCL) In ASP.NET Core?
Razor Class Libraries (RCL) in ASP.NET Core allow developers to create and share UI components, views, and resources across multiple projects. This enables modular and reusable UI development within ASP.NET Core.
95. How Do You Manage Session State in ASP.NET Core?
Session state in ASP.NET Core allows developers to store and retrieve user-specific data across multiple requests. This facilitates the management of user sessions and maintenance of stateful interactions.
96. What is the purpose of the IWebHostBuilder interface in .NET Core?
The IWebHostBuilder interface in .NET Core configures and builds the web host that will run on an application. It specifies the server, startup class, logging, and other configurations.
97. How Can You Implement Distributed Caching In .NET Core?
Distributed caching in .NET Core is the use of distributed cache systems like Redis or Memcached to store and retrieve frequently accessed data across multiple servers or instances. Doing this improves performance and scalability.
98. How Do You Optimize the Performance of A .NET Core Application?
A developer can do performance optimization in .NET Core through techniques, such as minimizing database round trips, optimizing query performance, using caching effectively, and using asynchronous programming to maximize responsiveness.
99. What is ASP.NET Core Identity?
This is a programming feature included in ASP.NET that can best implement user authorization and authentication in ASP.NET web applications. ASP..NET Core Identity is a customizable way to manage multiple user accounts and enforce access control in web applications. It also supports many authentication providers such as social media and enterprise identity.
100. Discuss .NET Interoperability
This is a component in .NET that allows developers to integrate with code written in other languages like C++ and Java. With .NET interoperability, developers can make use of components written in other languages in their applications.
Interview Preparation Tips
In this section, we will provide tips on how to approach .NET interviews and what to do in terms of format and process. We’ll also provide additional resources to help you as you prepare to interview candidates.
Common interview formats and types of questions
The current practice in the software development hiring process is to divide the interview into different parts or rounds. HR departments tend to have their approach so feel free to craft one that matches your organizational goals and recruitment practices.
First Round – Suitability Test
Many companies hiring .NET developers will initiate the interview process with a suitability test or introductory call. In the suitability test, you call the candidates, send a form or use other means of communication to ask them a few questions. You can ask one or two technical questions related to .NET to assess the candidate’s suitability.
The goal is to eliminate around 40% of candidates for senior .NET developer jobs and 60% for junior dev jobs in this round to make your work easier and to save time. It is therefore important to look for candidates that exude confidence and back their resume in the call. Verify that the information in their resume and cover letter is correct and up to date.
Second Round-Technical Interview
The technical interview stage is the most important when hiring both junior and senior .NET developers. It is where you gauge the candidate’s skills and depth of knowledge of .NET and software development concepts relevant to your company. Ideally, it should take up at least 60% of the entire interviewing process. We recommend having a senior .NET developer conduct these interview round.
The technical interview can include several technical questions or scenarios and problem-solving tests. Technical questions usually involve asking the candidate to define key .NET concepts like the CLR, C#, SQL, libraries, OOP, MVC patterns, LINQ, etc. Scenario or problem-solving questions should involve asking for sample code for a programming problem using a specific technology in dotNET.
The difficulty, complexity, and nature of technical questions and problems in the technical interview depend on the role to be filled. For instance, don’t ask about complex .NET topics like LINQ or Async if you are interviewing someone for a junior .NET developer position.
Most companies hiring .NET developers prefer to conduct technical interview rounds in a controlled environment.  The interview can be conducted virtually or physically but candidates shouldn’t be allowed to refer to their notes or research from a third-party source other than what you provide.
From our experience, a good number of interviewees fail technical interviews because they can’t resist the urge to refer to online sources. Excelling in the technical interview is a sign that the candidate is suitable for the .NET developer role and will be able to deliver if hired. However, technical skills are just a part of the puzzle and should not outweigh other assessments.
Third Round- Managerial Interview
Getting to the third round is an important milestone in the hiring process. It means the candidate is good .NET developer who can perform if hired. However, they need to impress the project manager and other stakeholders to be hired. Managerial interviews are designed to assess a candidate’s ability to fit into the role, team, and company culture as an employee.
For .NET development roles, ask them to demonstrate their understanding of software development methodologies like Agile for example, and the tools they use like GitHub. Also, ask or test them on communication skills, teamwork, task management, aptitude, and attitude. You may also opt to test NET. developers on specific project-based skills like testing, code security, debugging, coding style, etc.
Fourth Round- Negotiation and Onboarding
At this stage, you have probably selected the candidate for the open position and the company is willing to talk about compensation and other aspects of the job with them. The negotiation and onboarding stage of most .NET interviews is usually conducted by the human resources team.
If successful in the fourth round, the recruitment team should prepare a time-limited offer. Request the candidate to review the offer and respond in good time. This will allow you time to choose other candidates or put them to their roles as soon as possible.
Practice Resources and Study Materials
There are plenty of resources online you can use to prepare to interview .NET developers. The first one of course is our blog where you can find plenty of easy-to-read material on dotNET. Our articles are written from a practitioner’s perspective and are meant to educate and guide. Other practice resources you may find helpful are:
Microsoft .NET online documentation – The online .NET documentation is a great resource for reading about every aspect of .NET as described by the source.
Leet Code- Leet Code is the best online resource to practice asking scenario-based .NET technical interview questions and problems.
Neet Code- Neet Code is an excellent online resource to practice .NET development problems online.
GitHub learning repositories- There are plenty of repositories on GitHub to help you learn everything you need to interview .NET developers. Examples include:
- The tech interview handbookon GitHub
- The leedtcode repoon GitHub
- The interview universityrepo on GitHub
- The interviews repoon GitHub, etc.
Code Chef- Code Chef is an excellent online resource to refresh your knowledge of data structures and algorithms.
Conclusion
While acquired knowledge and experience are important in .NET developer interviews, it is important to prepare well by reading the documentation and practicing using online resources like Leet code. Ensure you understand the specific .NET technology you are interviewing people for and be open minded about the problem-solving approaches. All the best!
