Is there a difference?

[ShervanN]

Hello,

Two things:

1. I am not sure. Anyway, On page 542 ❘ CHAPTER 19 Networking, You wrote:

To create an application hosting the Kestrel server, you can create an empty web application with the .NET CLI:
dotnet new web.

dotnet new web command will create an asp.net core app with Top-level statements, while your descriptions (in a few lines later) are based without this feature.

2. On page 543, When I execute dotnet new web in .NET 7, I have the below snippet in Program class,

namespace web2;

public class Program
{
    public static void Main(string[] args)
    {
        var builder = WebApplication.CreateBuilder(args);
        var app = builder.Build();

        app.MapGet("/", () => "Hello World!");

        app.Run();
    }
}

While snippet code in your book is:

using Microsoft.AspNetCore.Hosting;

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }
    public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
    .ConfigureWebHostDefaults(webBuilder =>
    {
        webBuilder.UseStartup<Startup>();
    });
}

Does the text of the book and the code in this section need to be updated?

[christiannagel]

.NET 6 added the WebApplication and WebApplicationBuilder classes which abstracts away the Host class and removes the requirement of the Startup class.

The code in repo has been updated already. Now I also added information to the readme files:

https://github.com/ProfessionalCSharp/ProfessionalCSharp2021/blob/main/Dotnet6Updates.md

https://github.com/ProfessionalCSharp/ProfessionalCSharp2021/blob/main/2_Libs/Networking/Readme.md

Also check this:

Upgrading an ASP.NET Core Web API Project to .NET 6 - Article

Upgrading an ASP.NET Core Web API Project to .NET 6 - Source Code

[ShervanN]

Thank you, How about the first question?

[christiannagel]

I thought this was already included in the answer - but the first question was about the top-level statements?

Contrary to the opinion of reviewers I used top-level statements with most of the book samples when authoring the book. A reviewer complained the readers would be confused when the top-level statements are not created on creation of the application. The templates with .NET 6 changed to top-level statements - which I was expecting.

Now, most program templates create an initial application with top-level statements. With web applications before .NET 6, using top-level statements was not that big of an advantage because of the requirement of the Startup class. With .NET 6, the WebApplication and WebApplicationBuilder classes have been introduced. These classes simplify the startup code a lot by using top-level statements.

If you like, you can create a program without top-level statements with:

dotnet new web --use-program-main