Web Applications

This section covers the development of web applications using the .NET ecosystem. .NET provides powerful frameworks and tools to build modern, scalable, and secure web applications.

Overview of .NET Web Development

The .NET platform offers several robust frameworks for web development, each suited for different needs:

ASP.NET Core: A cross-platform, high-performance, open-source framework for building modern, cloud-based, internet-connected applications. It's the recommended framework for new web development projects.
ASP.NET Web Forms: An older, but still supported, framework that uses a component-based model and event-driven programming for building dynamic web pages.
ASP.NET MVC: A framework that implements the Model-View-Controller (MVC) design pattern, providing a clean separation of concerns and full control over HTML, CSS, and JavaScript.
Blazor: A framework for building interactive client-side web UIs with .NET. It enables you to use C# for front-end development, running either on the server or in the browser.

Key Concepts in .NET Web Applications

Understanding these core concepts is crucial for building effective web applications:

HTTP and Web Fundamentals: How web requests and responses work, including HTTP methods, status codes, and headers.
Routing: How incoming requests are mapped to specific code that handles them.
Middleware: Components that process HTTP requests and responses in a pipeline.
Dependency Injection: A design pattern for achieving inversion of control and loose coupling.
State Management: Techniques for managing user session data across multiple requests.
Authentication and Authorization: Securing your web applications.
Razor Syntax: The templating engine used in ASP.NET Core and Blazor for embedding server-side code within HTML.

Getting Started with ASP.NET Core

ASP.NET Core is the modern, cross-platform framework for building web applications with .NET. Here's a basic example of a simple web application:

Example: A Basic "Hello World" Page

You can create a new ASP.NET Core Web Application project using Visual Studio or the .NET CLI.

Consider a simple Razor Page located at Pages/Index.cshtml:


@page
@model IndexModel
@{
    ViewData["Title"] = "Home Page";
}

<div class="text-center">
    <h1 class="display-4">Welcome</h1>
    <p>Learn about <a href="https://docs.microsoft.com/aspnet/core">building Web apps with ASP.NET Core</a>.</p>
    <p>Current time: @DateTime.Now.ToString()</p>
</div>

The corresponding code-behind file (Pages/Index.cshtml.cs) might look like this:


using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;

namespace MyWebApp.Pages
{
    public class IndexModel : PageModel
    {
        private readonly ILogger<IndexModel> _logger;

        public IndexModel(ILogger<IndexModel> logger)
        {
            _logger = logger;
        }

        public void OnGet()
        {
            _logger.LogInformation("Index page loaded.");
        }
    }
}

Resources

Explore the links above for in-depth guides, tutorials, and API references to master .NET web application development.