> ## Documentation Index > Fetch the complete documentation index at: https://interview.anantapoudel.com/llms.txt > Use this file to discover all available pages before exploring further. # Introduction A complete, structured guide for mastering .NET and C# at an intermediate and senior level.\ This documentation is divided into five main pillars, each containing detailed technical topics, best practices, and interview-grade explanations. *** ## 1. C# Language & Core Programming This section builds a strong foundation in the C# language and its underlying concepts. ### C# Language Fundamentals * Data types, variables, and constants * Value types vs reference types * Type casting and conversions * Nullable types * `var`, `dynamic`, and `object` * Strings and interpolation * Control flow (`if`, `switch`, loops) * Arrays and collections * Structs and enums * `readonly` and `const` * Pattern matching * Tuples and deconstruction * Indexers and ranges (`^`, `..`) * XML documentation ### Object-Oriented Programming (OOP) * Classes and objects * Inheritance and polymorphism * Abstract classes and interfaces * Encapsulation and access modifiers * Constructors and destructors * Static members and singletons * Sealed classes * Partial classes and records * Method hiding (`new`) * Virtual vs override ### Advanced C# Concepts * Delegates and events * Lambda expressions * Extension methods * Reflection and attributes * Generics and constraints * Nullable reference types * Expression-bodied members * Records and immutability * Operator overloading * File-scoped namespaces * Global using directives * `Span` and `Memory` *** ## 2. Collections, LINQ & Asynchronous Programming Master the tools that make .NET development fast, expressive, and scalable. ### Collections & Generics * Arrays, Lists, Dictionaries, HashSet, Queues, Stacks * ReadOnlyCollection and concurrent collections * Immutable collections ### LINQ * Query syntax vs method syntax * Filtering, projection, grouping, joining * Aggregation functions * Deferred vs immediate execution * Custom extension methods * Parallel LINQ (PLINQ) ### Asynchronous Programming * Tasks and threads * `async` and `await` pattern * Task-based Asynchronous Pattern (TAP) * `Task.WhenAll` and `Task.WhenAny` * Synchronization (`lock`, `SemaphoreSlim`) * Cancellation tokens * Deadlocks and prevention * Background services and hosted services * Using `ValueTask` for performance *** ## 3. ASP.NET Core, Web API, EF Core & Architecture This section covers the main components of building robust backend applications with .NET. ### .NET Core Fundamentals * CLR, JIT compilation, GC * Project structure (`Program.cs`, hosting model) * Kestrel web server * Middleware pipeline * Configuration providers * Dependency injection system ### ASP.NET Core MVC & Razor * Controllers, views, and models * Razor syntax, layouts, partial views * Tag helpers * Model binding and validation * ViewData, ViewBag, TempData * Anti-forgery tokens ### ASP.NET Core Web API * `[ApiController]` basics * Routing and attribute routing * Action results and response shaping * Swagger/OpenAPI * File uploads and streaming * Pagination, filtering, sorting * API throttling and rate limiting ### Entity Framework Core (EF Core) * `DbContext` and `DbSet` * Code-first migrations * Relationship configuration * Loading strategies (lazy/eager/explicit) * Transactions and concurrency * Change tracking * Raw SQL execution * Repository and Unit of Work patterns ### SQL Server & Data Design * Normalization vs denormalization * Indexes and keys * Joins and query optimization * Stored procedures, views, triggers * CTEs and window functions *** ## 4. Security, Testing, Performance & Deployment A senior .NET developer must excel in building secure, performant, and well-tested systems. ### Authentication & Authorization * ASP.NET Core Identity * Claims and roles * Policy-based authorization * JWT authentication * OAuth2 and OpenID Connect * Refresh tokens * External providers ### Validation & Middleware * Data annotations * Custom validation attributes * FluentValidation * Custom middleware * Filters (resource, action, exception) ### Performance & Caching * In-memory and distributed caching * Response and output caching * Compression middleware * EF query optimization * BenchmarkDotNet * Asynchronous I/O ### Logging & Monitoring * `ILogger` usage * Serilog, NLog integration * Centralized logging (Seq, ELK, App Insights) * Distributed tracing with OpenTelemetry * Health checks ### Testing * xUnit, NUnit, MSTest * Moq for mocking * FluentAssertions * EF Core in-memory testing * Integration testing with `TestServer` *** ## 5. Microservices, Messaging, Cloud & System Design Master modern distributed system design with .NET and cloud platforms. ### Microservices & Distributed Systems * Microservices principles * Communication patterns (HTTP, gRPC) * API gateways (Ocelot, YARP) * Resilience with Polly (retry, circuit breaker) * Distributed tracing and correlation IDs ### Messaging & Background Jobs * RabbitMQ, Kafka, Azure Service Bus * Background workers (`IHostedService`) * Worker Service templates * Hangfire / Quartz.NET scheduling * Event-driven design ### Cloud Deployment & DevOps * Docker and multi-stage builds * Kubernetes basics * CI/CD pipelines (GitHub Actions, Azure DevOps) * Monitoring (Prometheus, Grafana) * Deployment slots and rolling updates ### Architecture & System Design * Clean Architecture * Onion Architecture * CQRS and Mediator pattern * Event Sourcing and DDD * Monolith vs microservices * Load balancing and caching * Database sharding and partitioning * Idempotent API design *** # Start Learning Choose a topic below to begin your .NET learning journey. Learn the fundamentals and deeper internals of the C# language. Master LINQ, generics, tasks, async/await, and advanced C# features. Build robust backend applications using Web API and EF Core. Learn how to secure, test, and optimize enterprise .NET applications. Advanced architecture, messaging, cloud deployments, and distributed systems.