ASP.NET Core Self-Hosting with a .NET 5 Windows Forms App

Demonstrates how to self-host an ASP.NET Core app using a .NET 5 Windows Forms app.

Self-Hosted MVC Core with a .NET 5 Windows Forms App

1. Add a new .NET 5 Windows Forms project.

2. Update the Project SDK in .csproj file to Web.

   • Add .Web to Microsoft.NET.Sdk

   <Project Sdk="Microsoft.NET.Sdk.Web">
       <PropertyGroup>
           <OutputType>WinExe</OutputType>
           <TargetFramework>net5.0-windows</TargetFramework>
           <UseWindowsForms>true</UseWindowsForms>
       </PropertyGroup>
   </Project>

3. Add a Startup class.

   • Configure Mvc core with Json formatters.

   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.AddControllers();
       }
   
       // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
       public void Configure(IApplicationBuilder app)
       {
           app.UseRouting();
   
           app.UseEndpoints(endpoints =>
           {
               endpoints.MapControllers();
           });
       }
   }

4. Add a CreateWebHostBuilder method to Program.cs.

   public static IHostBuilder CreateHostBuilder() =>
       Host.CreateDefaultBuilder()
           .ConfigureWebHostDefaults(webBuilder =>
           {
               webBuilder.UseStartup<Startup>();
           });

   • Add a static Form property.

   public static MainForm Form { get; private set; }

   • Call the method asynchronously from Main.
   • Set Form property and pass to Application.Run.

   static void Main()
   {
       CreateHostBuilder().Build().RunAsync();
       Application.SetHighDpiMode(HighDpiMode.SystemAware);
       Application.EnableVisualStyles();
       Application.SetCompatibleTextRenderingDefault(false);
       Form = new MainForm();
       Application.Run(Form);
   }

5. Add a TextBox to the main form.

   • Name it: nameTextBox
   • Add a NameText property
   • Use SynchronizationContext for the setter

   public partial class MainForm : Form
   {
       private SynchronizationContext _syncRoot;
   
       public MainForm()
       {
           InitializeComponent();
           _syncRoot = SynchronizationContext.Current;
       }
   
       public string NameText
       {
           get { return nameTextBox.Text; }
           set { _syncRoot.Post(SetName, value); }
       }
   
       private void SetName(object arg)
       {
           string name = arg as string;
           if (name != null)
               nameTextBox.Text = name;
       }
   }

6. Add a GreetingController with Get and Post methods.

   • Get and set the NameText property on the main form

   [Route("/hello")]
   public class GreetingController
   {
       [HttpGet]
       public IActionResult Get()
       {
           var name = Program.Form.NameText;
           var greeting = "Hello " + name;
           return new JsonResult(greeting);
       }
   
       [HttpPost]
       public IActionResult Post([FromBody] string name)
       {
           Program.Form.NameText = name;
           return new NoContentResult();
       }
   }

7. Use an http client such as Fiddler or Postman to send requests

   • Uri: http://localhost:5000/hello/
   • Add Accept and Content-Type headers: application/json

8. Add a .NET Core console app to send requests.

   • Add NuGet packages:
     • Microsoft.Extensions.Http
     • Newtonsoft.Json
   • Use HttpClient to send Post and Get requests.