In this tutorial, we will be walking through the process of creating a simple "Hello World" Application using Razor Pages and .NET Core. Razor Pages is a powerful web development framework that allows developers to build web applications using C# and the Razor templating engine. It provides a familiar and easy-to-use model-view-controller (MVC) pattern, along with a built-in dependency injection (DI) framework and support for asynchronous programming. This guide will provide you with step-by-step instructions for creating your first Razor Pages application, and serve as a starting point for building more complex web applications. So, let's get started!

1. Open Visual Studio and create a new project using the "ASP.NET Core Web Application" template.
2. Select the "Web Application" template and make sure "Razor Pages" is selected.
3. In the "Pages" folder, create a new Razor Page called "HelloWorld.cshtml".
4. In the "HelloWorld.cshtml" file, add the following code to the PageModel:

   public class HelloWorldModel : PageModel
   {
   public string Message { get; set; } = "Hello World!";
   }
   

5. In the "HelloWorld.cshtml" file, add the following code to the HTML section:

   @Model.Message
   
   

6. In the "Startup.cs" file, add a new route for the "HelloWorld" page:

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

7. Run the application and navigate to the "HelloWorld" page by typing "/HelloWorld" in the address bar.

And that's it! You have created your first "Hello World" application using Razor Pages with .NET Core. You can now continue to build on this foundation and create more complex web applications.