ASP.NET Tutorial - Hello World in 10 minutes

September 17, 2020

In the command prompt, run the following commands:

dotnet new webApp -o myWebApp --no-https

cd myWebApp

What do these commands mean? The dotnet new command creates a new application.

The webApp parameter selects what template to use when creating your app.
The -o parameter creates a directory named myWebApp where your app is stored.
The --no-https flag specifies not to enable HTTPS.
The cd myWebApp command puts you into the newly created app directory.

What files were created? Several files were created in the myWebApp directory, to give you a simple web application that is ready to run.

Startup.cs contains all the settings and configurations

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace myWebApp
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
            }

            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapRazorPages();
            });
        }
    }
}

The myWebApp/Pages directory contains some example web pages for the application.

Example: index.html

@page
@model IndexModel
@{
    ViewData["Title"] = "Home page";
}
<div class="text-center">
    <h1>Hello, world!</h1>
    <p>The time on the server is @DateTime.Now</p>
</div>

myWebApp.csproj defines what libraries are referenced etc.

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>

</Project>