DotNetInterviews

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Work through the essentials, mark each question when you can explain it, and keep your progress in this browser.

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OOPS

Build a strong foundation in object-oriented design.

0/8 done

What is OOPS and why is it useful?Solution

What is the difference between a class and an object?Solution

What is inheritance and which types does C# support?Solution

What is polymorphism? Compare overloading and overriding.Solution

Explain abstraction and encapsulation with a practical example.Solution

When should you use an interface instead of an abstract class?Solution

What is method overloading and how does it differ from method overriding?Solution

What are constructors and destructors in C#?Solution

SOLID Principles

Practice the design principles that keep object-oriented code maintainable.

0/6 done

What are the SOLID principles and why do they matter?Solution

What is the Single Responsibility Principle?Solution

How does the Open/Closed Principle guide extension and modification?Solution

What is the Liskov Substitution Principle?Solution

How does the Interface Segregation Principle improve interfaces?Solution

What is Dependency Inversion and how does dependency injection support it?Solution

C# Fundamentals

Review the language features that appear in everyday interviews.

0/16 done

What is the difference between value types and reference types?Solution

What is the difference between ref, out, and in parameters?Solution

What are delegates and events?Solution

How do async and await work in C#?Solution

What is IDisposable and how does the using statement help?Solution

What is boxing and unboxing in C#?Solution

What is the difference between var, dynamic, and object in C#?Solution

What is LINQ and how is it used in C#?Solution

What are the differences between IEnumerable, ICollection, IList, and IQueryable?Solution

What are the differences between structs and records in C#?Solution

What are attributes and how does reflection work in C#?Solution

What is the difference between const, readonly, and static in C#?Solution

What is the purpose of the using statement in C#?Solution

What are generics in C# and how do they improve type safety?Solution

What is the difference between throw and throw expressions in C#?Solution

What is the difference between synchronous and asynchronous programming in C#?Solution

ASP.NET Core

Understand how web applications are composed and served.

0/13 done

How does the ASP.NET Core request pipeline work?Solution

Explain dependency injection lifetimes: transient, scoped, and singleton.Solution

What is middleware and how do you write custom middleware?Solution

How do authentication and authorization differ?Solution

Explain MVCSolution

What are different types of exception handling in ASP.NET Core?Solution

How does garbage collection work in .NET?Solution

How does logging work in ASP.NET Core?Solution

How does ASP.NET Core work with IIS?Solution

What is Kestrel and how does it serve requests?Solution

How do cookies and sessions work in ASP.NET Core?Solution

What are caching strategies in ASP.NET Core?Solution

What is the difference between Dispose and Finalize in ASP.NET Core?Solution

SQL and Entity Framework

Practice data access, queries, and performance fundamentals.

0/20 done

What is Entity Framework Core and how does it work?Solution

What is DbContext and how does it manage database connections?Solution

What is DbSet and how does it represent a table in EF Core?Solution

What is the difference between lazy loading and eager loading in EF Core?Solution

What is the difference between tracking and no-tracking queries in EF Core?Solution

How does LINQ work with Entity Framework Core?Solution

What is change tracking in Entity Framework Core?Solution

How do EF Core migrations work?Solution

What are stored procedures, views, and functions in SQL?Solution

What are primary, unique, and foreign keys in SQL?Solution

What is the difference between DELETE, DROP, and TRUNCATE in SQL?Solution

What are transaction isolation levels in SQL?Solution

What is the difference between SQL and NoSQL databases?Solution

What is the difference between VARCHAR and NVARCHAR in SQL?Solution

What is the difference between UNION and UNION ALL in SQL?Solution

Explain the common SQL joins and when to use them.Solution

What is an index and when can it hurt performance?Solution

What is a deadlock in SQL and how can it be resolved?Solution

What does ACID stand for in database transactions?Solution

What are triggers in SQL and when should they be used?Solution

Web API and System Design

Connect backend concepts to resilient, maintainable services.

0/9 done

What makes an API RESTful?Solution

What are the common HTTP methods and when should they be used?Solution

What are common HTTP headers used in REST APIs?Solution

What is CORS and how does it affect API requests?Solution

What is the difference between authentication and authorization in APIs?Solution

Which HTTP status codes should an API return for common outcomes?Solution

What are practical approaches to API versioning?Solution

How would you design caching for a read-heavy service?

How would you scale a .NET API as traffic grows?

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