.NET Application Development Flashcards

Which .NET Framework class provides a thread-safe, first-in-first-out (FIFO) collection?

Answer: ConcurrentQueue

ConcurrentQueue in System.Collections.Concurrent is a thread-safe FIFO collection designed for multi-threaded scenarios.

What does the [Obsolete] attribute do in .NET?

Answer: Marks a member as deprecated and generates a compiler warning or error

[Obsolete] signals that a member should no longer be used and can produce a compiler warning or error when it is referenced.

In LINQ, what is the difference between deferred and immediate execution?

Answer: Immediate execution runs the query when defined; deferred runs when iterated

Most LINQ operators use deferred execution — the query is built when defined but runs only when the result is enumerated.

Which ASP.NET state management option stores data on the server and uses a cookie only to identify the session?

Answer: Session State

Session State stores data server-side and uses a session ID (sent via cookie or URL) to associate data with a specific user.

What is the output of calling String.Intern() in .NET?

Answer: It returns a reference to a shared, interned string from the pool

String.Intern() retrieves a reference to the canonical instance of the string from the intern pool, enabling reference equality checks.

In C#, what is the purpose of an abstract method?

Answer: It declares a method signature with no implementation that subclasses must override

An abstract method has no body in the base class and forces every concrete subclass to provide its own implementation.

Which .NET mechanism allows you to call a method asynchronously using a delegate?

Answer: BeginInvoke() / EndInvoke()

Delegates expose BeginInvoke() to start an asynchronous call and EndInvoke() to retrieve the result — the classic .NET async pattern.