Embarking on a career as a .NET developer? Congratulations! You're about to join a thriving community of developers who leverage Microsoft's powerful technology stack. To help you prepare for your interview, we've collated some of the most frequently asked .NET interview questions, ranging from fundamental concepts to more advanced topics.
Before diving into the questions, ensure you have a solid understanding of core .NET concepts, such as C# syntax, MVVM pattern, asynchronous programming, and working with abstract classes and interfaces. Also, brush up on your knowledge of .NET frameworks, libraries, and the overall ecosystem.
.NET Fundamentals
The interviewer will likely start by assessing your understanding of basic .NET concepts. Here are some questions you might encounter:
What is the difference between async and async void methods?
Async methods allow you to propagate exceptions to the caller, while async void methods do not. Async void methods are typically Used for async event handlers, and they can lead to challenges when debugging.
In example, async void DoWork() can cause difficulties in tracking exceptions, whereas async Task DoWork() allows you to maintain the exception hierarchy.
Can you explain the difference between struct and class in C#?
In C#, structs are value types, while classes are reference types. Structs are typically used for small data structures or value containers, while classes are used for larger, more complex objects. Some key differences include inheritance (classes can inherit from other classes, while structs cannot), default values (structs default to zero or null for primitive types, while classes default to null), and nullability (structs cannot be null, while classes can).
.NET Core and ASP.NET Core
With the introduction of .NET Core and ASP.NET Core, understanding the evolution of these frameworks is crucial. Be prepared to discuss the following:
What is the difference between .NET Framework and .NET Core?
.NET Core is a cross-platform, open-source version of .NET that can run on Windows, Linux, and macOS. It is modular, making it lighter and more flexible. .NET Framework, on the other hand, is primarily for Windows and has a fuller set of features. .NET Core can now run on Windows, and the two are uniting under .NET 5 and later.
In terms of performance, .NET Core often provides better throughput and lower memory usage due to its more lightweight design.
Can you explain middleware in ASP.NET Core?
Middleware in ASP.NET Core is responsible for handling HTTP requests and responses. It enablescross-cutting concerns such as authentication, authorization, logging, and compression. Each middleware component processes the request sequentially, with the ability to Short-circuit the pipeline and stop execution of subsequent middleware components.
In an example, app.UseAuthentication(); and app.UseAuthorization(); are middleware methods that handle authentication and authorization, respectively. They must be added in the correct order to function properly.
Embracing the ever-evolving landscape of .NET is key to success in your developer career. Stay curious, and continue exploring the numerous resources and communities dedicated to this powerful framework! Good luck with your interview!