MSDN Documentation

Introduction to .NET Web Development

Welcome to the comprehensive guide on building modern web applications using the .NET ecosystem. .NET offers a powerful, flexible, and high-performance platform for developing a wide range of web applications, from simple APIs to complex, enterprise-grade solutions.

This documentation will guide you through the essential concepts, frameworks, and best practices for web development in .NET.

ASP.NET Core

ASP.NET Core is Microsoft's modern, open-source, and cross-platform framework for building web applications. It's a significant evolution from previous ASP.NET versions, designed for cloud-native development and high performance.

Model-View-Controller (MVC)

The MVC pattern is a popular architectural pattern for building web applications. ASP.NET Core MVC provides a structured way to organize your code into three distinct concerns:

• Model: Represents the data and business logic.
• View: Handles the presentation logic (UI).
• Controller: Acts as an intermediary, handling user input, interacting with the Model, and selecting a View to render.

using Microsoft.AspNetCore.Mvc;

public class HomeController : Controller
{
    public IActionResult Index()
    {
        var message = "Welcome to ASP.NET Core MVC!";
        return View("Index", message);
    }

    [HttpGet]
    public IActionResult Contact()
    {
        return View();
    }

    [HttpPost]
    public IActionResult Contact(ContactViewModel model)
    {
        if (ModelState.IsValid)
        {
            // Process contact form submission
            return RedirectToAction("ThankYou");
        }
        return View(model);
    }
}
                

Razor Pages

Razor Pages is an alternative, page-focused programming model that makes it easier to build web UI with .NET. It simplifies the development of event-driven, server-rendered UI scenarios, often requiring less boilerplate code than MVC for simpler pages.

• Each page is represented by a C# class (page model) and an HTML template using Razor syntax.
• Ideal for scenarios where UI logic is tightly coupled to a specific page.

Web API

ASP.NET Core Web API is a framework for building HTTP services that can be consumed by a wide range of clients, including web browsers, mobile apps, and other services. It's commonly used to build RESTful APIs.

• Supports standard HTTP verbs (GET, POST, PUT, DELETE).
• Easy integration with JSON and XML formatting.
• Built-in support for routing, model binding, and validation.

Blazor

Blazor is a modern web framework from Microsoft for building interactive client-side web UIs with .NET. It allows you to use C# for both client-side and server-side development, eliminating the need for JavaScript in many scenarios.

Blazor Server

In Blazor Server applications, UI events are sent to the server via SignalR, and the UI updates are then sent back to the client. This keeps your C# code running on the server.

Blazor WebAssembly (WASM)

Blazor WebAssembly allows you to run C# code directly in the browser using WebAssembly. This provides a true client-side web development experience with .NET, enabling rich, interactive UIs with excellent performance.

Data Access in .NET Web Applications

Effectively managing data is crucial for any web application. .NET provides robust tools and frameworks for interacting with databases.

Entity Framework Core (EF Core)

EF Core is a modern, cross-platform Object-Relational Mapper (ORM) that enables .NET developers to work with databases using domain-specific objects. It simplifies database access by abstracting away much of the raw SQL.

• Supports Code-First, Database-First, and Model-First approaches.
• Powerful LINQ queries for data manipulation.
• Migrations for managing database schema changes.

using (var context = new MyDbContext())
{
    var products = await context.Products
                                .Where(p => p.IsAvailable && p.Price > 50)
                                .OrderByDescending(p => p.Name)
                                .ToListAsync();

    foreach (var product in products)
    {
        Console.WriteLine($"{product.Name} - ${product.Price}");
    }
}
                

ADO.NET

ADO.NET provides a core set of classes for interacting with data sources. While EF Core is often preferred for its abstraction, ADO.NET offers lower-level control and can be more performant for highly optimized scenarios or when direct SQL is necessary.

Deployment Strategies

Deploying your .NET web application efficiently and reliably is key. ASP.NET Core applications can be deployed in various ways:

• Self-Contained Deployment: Includes the .NET runtime and libraries with your application.
• Framework-Dependent Deployment: Relies on a shared .NET runtime installed on the target machine.
• Containerization: Using Docker to package your application and its dependencies for consistent deployment across environments.
• Cloud Platforms: Azure App Service, AWS Elastic Beanstalk, Google App Engine, and others offer managed hosting solutions.

Security Best Practices

Securing your web applications is paramount. ASP.NET Core provides built-in features and encourages best practices:

• Authentication & Authorization: Implement robust mechanisms to verify user identity and control access to resources.
• Input Validation: Sanitize all user input to prevent injection attacks (SQL injection, XSS).
• HTTPS: Enforce the use of HTTPS to encrypt communication.
• Secure Configuration: Manage secrets and sensitive configuration data securely (e.g., using Azure Key Vault or User Secrets).
• Dependency Management: Keep all libraries and frameworks updated to patch known vulnerabilities.
• Cross-Site Request Forgery (CSRF) Protection: Utilize built-in anti-CSRF tokens.