ASP.NET

What is ASP.NET?

ASP.NET is an open-source, server-side web-application framework designed for web development to produce dynamic web pages. It was developed by Microsoft to allow programmers to build dynamic web sites, web applications and web services.

Creating Your First ASP.NET Application

You can create an ASP.NET application using the 'New Project' wizard in Visual Studio.

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ASP.NET Core Middleware

Middleware in ASP.NET Core is software that is assembled into an app pipeline to handle requests and responses. Each component in the request pipeline is chosen to handle a specific task.

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    else
    {
        app.UseExceptionHandler('/Home/Error');
    }
    app.UseStaticFiles();

    app.UseRouting();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllerRoute(
            name: 'default',
            pattern: '{controller=Home}/{action=Index}/{id?}');
    });
}

Working with Controllers

Controllers in ASP.NET Core MVC are classes that handle incoming HTTP requests and send the response back to the client. The Controller base class provides several methods and properties useful in handling HTTP requests.

public class HomeController : Controller
{
    public IActionResult Index()
    {
        return View();
    }
}

Routing

Routing in ASP.NET Core is how ASP.NET Core matches a URI to an action. ASP.NET Core routing is based on a middleware that you can customize as necessary.

app.UseEndpoints(endpoints =>
{
    endpoints.MapControllerRoute(
        name: 'default',
        pattern: '{controller=Home}/{action=Index}/{id?}');
});

Entity Framework Core

Entity Framework (EF) Core is an open source, lightweight, extensible and a cross-platform version of Entity Framework data access technology. EF Core serves as an object-relational mapper (O/RM), which enables .NET developers to work with a database using .NET objects, eliminating the need for most of the data-access code they usually need to write.

public class Blog
{
    public int BlogId { get; set; }
    public string Url { get; set; }

    public List<Post> Posts { get; set; }
}

public class Post
{
    public int PostId { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }

    public int BlogId { get; set; }
    public Blog Blog { get; set; }
}

Migrations

Migrations provide a way to incrementally apply schema changes to the database to keep it in sync with your EF Core model while preserving existing data in the database.

Add-Migration InitialCreate
Update-Database

Working with Views

Views in ASP.NET Core handle the app's data presentation and user interaction. A view is an HTML template with embedded Razor markup.

@{
    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>
</div>

Razor Views

Razor is a markup syntax for embedding server-based code into webpages. The Razor syntax consists of Razor markup, C# and HTML. Files containing Razor generally have a .cshtml file extension.

@{
    ViewData['Title'] = 'Home Page';
}

<div class='text-center'>
    <h1>@ViewData['Title']</h1>
    <p>Welcome to our application.</p>
</div>

Authentication

ASP.NET Core provides several tools to customize the authentication process where you can configure your application to authenticate the user via cookies, via third-party providers, or another method.

services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
    .AddCookie(options =>
    {
        options.LoginPath = '/Account/Unauthorized/';
        options.AccessDeniedPath = '/Account/Forbidden/';
    });

Authorization

With authorization, you can control access to certain parts of your application depending on the user's role or claim.

[Authorize(Roles = 'Admin')]
public class AdminController : Controller
{
    // Controller methods here
}

ASP.NET Core Identity

ASP.NET Core Identity is a membership system that adds login functionality to your application. It provides services and APIs for user registration, authentication, and authorization, as well as managing a user's profile.

// This usually goes into the ConfigureServices method of your Startup class.
services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
    .AddEntityFrameworkStores<ApplicationDbContext>();

Deployment Basics

There are a number of ways to deploy an ASP.NET Core application. One common approach is to use a service like Azure App Service or IIS.

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Deploying to Azure

Azure App Service is a fully managed platform for building, deploying, and scaling your web apps. You can deploy your ASP.NET Core application to Azure using Visual Studio or the Azure CLI.

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Deploying to IIS

Internet Information Services (IIS) for Windows Server is a flexible, secure, and easy-to-manage Web server for hosting anything on the Web. You can host your ASP.NET Core application on IIS.

// IIS deployment doesn't have a direct code example.