.NET interview preparation guide - aniketmulmule/web_Project GitHub Wiki

Here’s a comprehensive .NET interview preparation guide for professionals with 8+ years of experience, covering core topics, advanced C# concepts, architecture, system design, soft skills, and behavioral questions.

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• Focus 60–70% on advanced C# and architecture

• Spend the rest on coding, design patterns, testing, and communication

---

Topic	What to Master	Resources
OOP (4 Pillars)	Advanced understanding + real-world examples	Microsoft Docs
Interface vs Abstract	Use cases, memory model
Access Modifiers	private, protected, internal, protected internal
readonly, const, static, sealed	Use cases and differences
Delegates, Events, Func/Action/Predicate	Scenarios, real-time examples
LINQ & Lambda	Query syntax, method syntax, performance tips
Exception Handling	Custom exceptions, logging best practices
Async/Await, Tasks, Threads	ConfigureAwait, deadlocks, sync context
Generics	Constraints, covariant/contravariant
Memory Management	GC, IDisposable, finalizers, weak refs
Reflection & Dynamic Features	Use cases, performance concerns
Nullable Reference Types	Avoiding NullReferenceException
Records, Tuples, Structs	Value vs reference, use cases

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• Mastered advanced C# language features

• Comfortable with async, memory, GC, LINQ

• Practiced system design and clean architecture

• Reviewed API security and performance

• Solved at least 25 C# problem-solving questions

• Prepared 3+ STAR stories for behavioral rounds

---

Would you like me to:

• 📄 Generate this as a PDF?

• 📊 Build a Notion/Excel tracker?

• 🧪 Create quiz sets or mock interview questions?

Let me know — I’ll get it done instantly.

Here’s a **comprehensive .NET interview preparation guide for professionals with 8+ years of experience**, covering **core topics, advanced C# concepts, architecture, system design, soft skills, and behavioral questions**.

---

• Focus 60–70% on advanced C# and architecture
• Spend the rest on coding, design patterns, testing, and communication

---

Topic	What to Master	Resources
OOP (4 Pillars)	Advanced understanding + real-world examples	[Microsoft Docs](https://learn.microsoft.com/en-us/dotnet/csharp/fundamentals/tutorials/oop)
Interface vs Abstract	Use cases, memory model
Access Modifiers	private, protected, internal, protected internal
readonly, const, static, sealed	Use cases and differences
Delegates, Events, Func/Action/Predicate	Scenarios, real-time examples
LINQ & Lambda	Query syntax, method syntax, performance tips
Exception Handling	Custom exceptions, logging best practices
Async/Await, Tasks, Threads	ConfigureAwait, deadlocks, sync context
Generics	Constraints, covariant/contravariant
Memory Management	GC, IDisposable, finalizers, weak refs
Reflection & Dynamic Features	Use cases, performance concerns
Nullable Reference Types	Avoiding NullReferenceException
Records, Tuples, Structs	Value vs reference, use cases

---

Topic	Focus	Resources
SOLID Principles	Code samples, violations, refactoring	[DevIQ - SOLID](https://deviq.com/principles/solid)
Design Patterns	Singleton, Factory, Strategy, etc.	[Refactoring Guru](https://refactoring.guru/design-patterns/csharp)
Dependency Injection	Scoped/Transient/Singleton, constructor injection
Clean Architecture	Layers, responsibilities, abstractions	[Clean Architecture by Steve Smith](https://github.com/ardalis/CleanArchitecture)
DDD (Domain-Driven Design)	Entities, aggregates, value objects
Microservices vs Monolith	When to choose what
CQRS / Event Sourcing (Basics)	Benefits and tradeoffs

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Tech	Key Concepts
.NET Framework vs .NET Core vs .NET 5/6/7	Cross-platform, performance, hosting
ASP.NET Core	Middleware, DI, Filters, Routing
Web API	REST principles, filters, versioning, throttling
Entity Framework	Code-first, migrations, lazy vs eager loading
Logging	Serilog, NLog, structured logging
Configuration	Options pattern, IOptions, secrets
Testing	xUnit, Moq, test coverage, integration testing
API Security	JWT, OAuth2, IdentityServer, claims-based auth
Blazor (optional)	Server vs WASM, real-time apps

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Topic	Must Know
Authentication vs Authorization	Role-based, claims-based
OWASP Top 10	SQL Injection, XSS, CSRF, etc.
IdentityServer / OpenID Connect	Basics and integration

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Focus Area	Key Prep
High-level system design	Design a scalable API, ecommerce, booking system
Data storage & caching	Redis, SQL, NoSQL, indexing
Performance & scaling	Horizontal vs vertical scaling, load balancing
Message Queues	RabbitMQ, Azure Service Bus, event-driven architecture
Async processing	Background services, queues, pub/sub
Monitoring	Health checks, metrics, logs

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Area	What to Practice
C# syntax	Real-time business logic problems
DSA (limited)	Arrays, strings, hashing, collections
LINQ queries	Filter, group, join, custom aggregations
File handling	Parsing, JSON/XML reading
Memory & performance	Optimize slow/GC-heavy code

Sites:

• [LeetCode (Easy/Medium)](https://leetcode.com/problemset/all/?difficulty=Easy)
• [Exercism C#](https://exercism.org/tracks/csharp)
• [DotNetFiddle](https://dotnetfiddle.net)

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Area	What to Prepare
STAR format answers	Situation, Task, Action, Result
Project architecture explanation	Diagram + justification
Handling legacy code	Refactoring strategies
Team leadership	Mentoring, code reviews, estimations
Conflict resolution	Clear examples
Stakeholder communication	Requirements gathering, demos

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• What’s the difference between IEnumerable and IQueryable?
• When would you use a record instead of a class?
• Explain ConfigureAwait(false) — why and when?

• How would you design a scalable login service?
• When would you use CQRS?
• Explain a system you’ve worked on and the patterns used.

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Tool	Use
[SharpLab](https://sharplab.io)	Explore how C# compiles
[DotNetFiddle](https://dotnetfiddle.net)	Try C# snippets online
[Postman](https://www.postman.com)	Test your Web APIs
[Draw.io](https://draw.io)	Create architecture diagrams

---

• Mastered advanced C# language features
• Comfortable with async, memory, GC, LINQ
• Practiced system design and clean architecture
• Reviewed API security and performance
• Solved at least 25 C# problem-solving questions
• Prepared 3+ STAR stories for behavioral rounds

---

Would you like me to:

• 📄 Generate this as a PDF?
• 📊 Build a Notion/Excel tracker?
• 🧪 Create quiz sets or mock interview questions?

Let me know — I’ll get it done instantly.