MSDN Documentation

Introduction to ASP.NET

ASP.NET is a free web framework for building modern web apps and services. It's developed by Microsoft and runs on the .NET platform. ASP.NET empowers you to use your existing knowledge and favorite tools to build robust and dynamic web applications.

With ASP.NET, you can build:

• Web Applications
• Web Services
• Single Page Applications (SPAs)
• APIs
• And more...

It supports various development models, offering flexibility to choose the best approach for your project. This documentation provides comprehensive resources, tutorials, and API references to help you master ASP.NET development.

Getting Started with ASP.NET

To start building ASP.NET applications, you'll need to install the .NET SDK. Download the latest version from the official .NET website.

Once installed, you can create your first project using the .NET CLI:

dotnet new webapp -o MyFirstApp
cd MyFirstApp
dotnet run

This command creates a new web application project and runs it, making it accessible via a local URL, typically https://localhost:5001.

ASP.NET Core Concepts

ASP.NET Core is the successor to ASP.NET and is a cross-platform, high-performance framework. Key concepts include:

• Middleware: Components that process HTTP requests and responses in a pipeline.
• Dependency Injection: A design pattern that facilitates managing dependencies and improves testability.
• Configuration: Flexible system for managing application settings.
• Routing: Mechanism for mapping incoming requests to specific handler methods.
• Model-View-Controller (MVC): A popular architectural pattern for building web applications.

ASP.NET MVC

ASP.NET MVC is a framework for building dynamic websites using a Model-View-Controller (MVC) architectural pattern. It separates concerns into three distinct parts:

• Model: Represents the data and business logic.
• View: Responsible for presenting the data to the user.
• Controller: Handles user input, interacts with the Model, and selects the View to render.

MVC provides a clean separation of concerns, making applications easier to maintain, test, and scale.

ASP.NET Web API

ASP.NET Web API is a framework for building HTTP services that can be accessed from a wide variety of clients. It's ideal for creating RESTful services.

Key features include:

• Building RESTful services on top of HTTP.
• Support for various content formats (JSON, XML).
• Easy integration with ASP.NET MVC.

Example of a simple Web API controller:

public class ProductsController : Controller
{
    [HttpGet]
    public IEnumerable<string> Get()
    {
        return new string[] { "Product 1", "Product 2" };
    }
}

Razor Pages

Razor Pages is a page-focused programming model for ASP.NET Core that makes it easy to build web UI with less code. It's a simpler alternative to MVC for many scenarios.

Each Razor Page consists of a Razor markup file (.cshtml) and an optional PageModel class (.cshtml.cs) that handles logic for the page.

Example Index.cshtml:

<h1>Hello, @Model.Name!</h1>

Example Index.cshtml.cs:

public class IndexModel : PageModel
{
    public string Name { get; set; }

    public void OnGet()
    {
        Name = "World";
    }
}

Blazor

Blazor is a .NET web framework for building interactive client-side web UIs with C# instead of JavaScript. It enables developers to build full-stack web applications entirely in C#.

Blazor supports two hosting models:

• Blazor Server: Runs the application logic on the server and communicates with the client via SignalR.
• Blazor WebAssembly: Runs the application directly in the browser using WebAssembly.

With Blazor, you can create reusable UI components using C# and Razor syntax.

Data Access with ASP.NET

ASP.NET applications commonly interact with databases. The most popular ORM (Object-Relational Mapper) for .NET is Entity Framework Core.

Entity Framework Core allows you to work with a database using .NET objects, abstracting away much of the SQL syntax. You can define your database schema using C# classes (Code-First) or map existing databases to your classes (Database-First).

Key aspects of data access:

• Defining models and DbContext.
• Migrations for schema changes.
• Querying data using LINQ.
• Saving changes to the database.

Security in ASP.NET

Security is a critical aspect of web development. ASP.NET Core provides robust features for securing your applications:

• Authentication: Verifying the identity of users. ASP.NET Core supports various authentication schemes like cookies, JWT, OAuth, and OpenID Connect.
• Authorization: Determining what authenticated users are allowed to do.
• Cross-Site Scripting (XSS) Prevention: ASP.NET Core automatically encodes output to prevent XSS attacks.
• Cross-Site Request Forgery (CSRF) Protection: Built-in support for preventing CSRF attacks.
• HTTPS: Encouraging and enforcing the use of HTTPS.

Deploying ASP.NET Applications

ASP.NET Core applications can be deployed to various platforms, including Windows, Linux, and macOS. Deployment options include:

• Self-Contained Deployment: The application includes the .NET runtime, so no separate .NET installation is required on the target machine.
• Framework-Dependent Deployment: The application depends on a .NET runtime installed on the target machine.
• Containerization: Deploying applications using Docker containers for consistency and portability.

Common deployment targets include:

• IIS (Internet Information Services) on Windows.
• Nginx or Apache on Linux.
• Cloud platforms like Azure, AWS, and Google Cloud.