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ASP.NET Core Introduction

📚 Lesson 1 of 15 ⏱️ 45 min

ASP.NET Core Introduction

45 min

ASP.NET Core is a cross-platform, high-performance framework for building modern, cloud-based, Internet-connected applications. ASP.NET Core is a complete rewrite of ASP.NET, designed from the ground up to be fast, modular, and cross-platform. It's used to build web applications, APIs, microservices, and real-time applications. ASP.NET Core's performance rivals Node.js and Go, making it suitable for high-throughput applications.

It's designed to be modular, allowing you to include only the components you need for your application. ASP.NET Core uses middleware pipeline architecture where you add only the components you need (authentication, CORS, routing, etc.). This modularity reduces application size and improves performance. Understanding the middleware pipeline helps you build efficient, customized applications.

ASP.NET Core runs on .NET Core, which is a cross-platform version of .NET that can run on Windows, macOS, and Linux. This cross-platform capability, combined with ASP.NET Core's performance, makes it competitive with other modern web frameworks. ASP.NET Core applications can be deployed to various platforms: Azure, AWS, Docker containers, or traditional servers. Understanding deployment options helps you choose the right hosting strategy.

ASP.NET Core supports multiple programming models: MVC (Model-View-Controller) for traditional web apps, Web API for RESTful services, Razor Pages for page-based apps, and minimal APIs for simple endpoints. Each model is suited for different use cases. Understanding these models helps you choose the right approach for your application. ASP.NET Core's unified programming model makes it easy to mix approaches when needed.

ASP.NET Core includes built-in dependency injection, making applications more testable and maintainable. The framework's dependency injection container manages object lifetimes and dependencies automatically. This enables loose coupling and makes unit testing easier. Understanding dependency injection is essential for building maintainable ASP.NET Core applications.

ASP.NET Core's configuration system is flexible and supports multiple sources (JSON files, environment variables, command-line arguments). This enables different configurations for development, staging, and production. ASP.NET Core includes built-in logging, which can be configured to write to various outputs. Understanding configuration and logging helps you build production-ready applications.

Key Concepts

  • ASP.NET Core is a cross-platform, high-performance web framework.
  • ASP.NET Core uses modular middleware pipeline architecture.
  • ASP.NET Core supports MVC, Web API, Razor Pages, and minimal APIs.
  • ASP.NET Core includes built-in dependency injection.
  • ASP.NET Core runs on .NET (cross-platform).

Learning Objectives

Master

  • Setting up ASP.NET Core development environment
  • Creating basic ASP.NET Core applications
  • Understanding middleware pipeline
  • Using dependency injection in ASP.NET Core

Develop

  • Understanding web application architecture
  • Appreciating ASP.NET Core's performance and features
  • Designing scalable web applications

Tips

  • Install .NET SDK: dotnet --version to verify installation.
  • Create new project: dotnet new webapi -n MyApi or dotnet new mvc -n MyWebApp.
  • Run application: dotnet run (development server on https://localhost:5001).
  • Use dotnet watch run for automatic reloading during development.

Common Pitfalls

  • Not understanding middleware order, causing unexpected behavior.
  • Not configuring CORS properly for API calls from browsers.
  • Not using dependency injection, making code hard to test.
  • Not understanding async/await, causing thread blocking.

Summary

  • ASP.NET Core is a modern, cross-platform web framework.
  • ASP.NET Core's modular architecture enables flexible application design.
  • ASP.NET Core provides high performance and comprehensive features.
  • Understanding ASP.NET Core enables building modern web applications.

Exercise

Create a basic ASP.NET Core web application that displays 'Hello, ASP.NET Core!'

using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", () => "Hello, ASP.NET Core!");

app.Run();

Exercise Tips

  • Create project: dotnet new web -n HelloWebApp.
  • Add more routes: app.MapGet("/about", () => "About page");
  • Use dependency injection: builder.Services.AddSingleton<IMyService, MyService>();
  • Add middleware: app.UseAuthentication(); app.UseAuthorization();

Code Editor

Output