ASP.NET Core Interview Questions and Answers

Answer: ORM for data access with object-to-database mapping

Entity Framework Core is an ORM (Object-Relational Mapper) that enables .NET developers to work with databases using .NET objects.

Answer: Cross-platform, high-performance framework for building web apps

ASP.NET Core is a cross-platform, open-source framework for building modern web applications and APIs. It runs on Windows, Linux, and macOS.

Answer: Real-time communication library for web sockets

SignalR enables real-time, bi-directional communication. Uses WebSockets when available, falls back to other transports. Use for chat, notifications, dashboards.

Answer: Session with database enabling queries and saves

DbContext represents a session with the database. It allows querying and saving data. Configure entity mappings and database connection.

Answer: ASP.NET Core is cross-platform and modular

ASP.NET Core is cross-platform (Windows, Linux, macOS), modular, open-source, and high-performance. ASP.NET Framework is Windows-only and monolithic.

Answer: High-performance RPC framework using HTTP/2

gRPC is high-performance RPC framework using HTTP/2 and Protocol Buffers. Faster than REST. Use for microservice communication.

Answer: Version control for database schema changes

Migrations provide version control for database schema. Create with Add-Migration, apply with Update-Database. Tracks schema changes over time.

Answer: Model-View-Controller architectural pattern

MVC (Model-View-Controller) separates application into three components: Models (data), Views (UI), Controllers (logic). Promotes separation of concerns.

Answer: Framework for building interactive web UIs with C#

Blazor builds interactive web UIs using C# instead of JavaScript. Blazor Server (server-side) or Blazor WebAssembly (client-side). Shares code with backend.

Answer: Handles requests and returns responses

Controllers handle incoming HTTP requests, process them (often interacting with models), and return responses (usually views or data).

Answer: Ensures data meets requirements before processing

Validation ensures data meets requirements. Use data annotations ([Required], [StringLength]) or FluentValidation. Automatic with model binding.

Answer: Caching shared across multiple servers

Distributed caching shares cache across multiple servers. Use Redis or SQL Server. Essential for load-balanced applications. Configure with IDistributedCache.

Answer: Presentation layer rendering HTML

Views are responsible for presenting data to users. They contain HTML markup with embedded Razor syntax for dynamic content.

Answer: In-memory caching for single server performance

Memory caching stores data in server memory. Fast but not shared across servers. Use IMemoryCache. Good for single-server or data that can differ.

Answer: Dictionary containing validation errors and values

ModelState contains model binding values and validation errors. Check ModelState.IsValid before processing. Display errors with validation tag helpers.

Answer: Compresses responses to reduce bandwidth

Response compression compresses HTTP responses (gzip, brotli). Reduces bandwidth, improves load times. Configure with AddResponseCompression().

Answer: Verifying user identity

Authentication verifies who the user is. ASP.NET Core supports various schemes: Cookies, JWT, OAuth2, OpenID Connect, Windows, Certificate.

Answer: Markup syntax combining C# and HTML

Razor is a markup syntax for embedding C# code into HTML. Uses @ symbol to transition between HTML and C#. Example: @Model.Name.

Answer: Determines what authenticated user can access

Authorization determines what an authenticated user can do. Use [Authorize] attribute, policies, role-based or claims-based authorization.

Answer: Limits request rate to prevent abuse

Rate limiting restricts number of requests per time period. Prevents abuse, DDoS. Use AspNetCoreRateLimit package or built-in (.NET 7+).

Answer: Abstracts data access layer for testability

Repository pattern abstracts data access layer. Provides interface for data operations. Improves testability and decouples business logic from data access.

Answer: Restricts access to authenticated users

[Authorize] restricts access to authenticated users. Apply to controllers or actions. Can specify roles or policies: [Authorize(Roles = "Admin")].

Answer: Page-focused framework alternative to MVC

Razor Pages is a page-focused framework that makes building web UI easier and more productive. Simpler than MVC for page-based scenarios.

Answer: Maintains list of objects and coordinates persistence

Unit of Work maintains list of affected objects and coordinates writing changes as one transaction. Often used with Repository pattern.