Top 4 Aspnet core Interview Questions

Browse 4 real-world technical and behavioral interview questions about Aspnet core. Review scenarios, edge cases, and architectural best practices.

You kick off background work from a controller action and it throws once the response has gone out. What is happening?

Detached ASP.NET Core background work can fail after the response because the request scope is disposed. Copy required values, create a fresh service scope, and run tracked work through IHostedService, BackgroundService or a durable queue.

mediumcoding

A client disconnects but your server keeps working on their request. How does cancellation actually propagate in .NET?

A CancellationToken in C# is cooperative cancellation, not a thread abort. Pass it through async calls, check it around long CPU loops, and define whether cancelled work leaves durable side effects behind.

mediumconcept

You added an authorisation policy to an ASP.NET Core endpoint and it is not being enforced. Where do you look?

The pipeline is an ordered list you assembled, and authorisation cannot decide anything before routing has selected an endpoint to decide about. Registered in the wrong order it either runs against nothing or never runs at all, and neither produces an error - the request simply succeeds.

mediumscenario

Why does calling .Result or .Wait() on an async method deadlock, and how do you fix it properly?

Blocking on async code with .Result or .Wait can deadlock when the awaited continuation needs the same SynchronizationContext that is blocked. In ASP.NET Core the common failure is thread-pool starvation; the fix is async all the way up.

hardconcept