This project is designed to be repeated not cloned or deployed from here ... please following the instructions below and use this site as a comparison for the final output.

• Install .NET 6.0 SDK
  • See https://dotnet.microsoft.com/en-us/download/dotnet/6.0
• Install VSCode
  • See https://code.visualstudio.com/Download

• Go to your projects/development folder
  • Such as cd c:\Development\
• Create first project and open in VSCode dotnet new web -n HelloNet cd HelloNet code .

• If loading .NET code for the first time you may be prompted to install OmniSharp and other extensions, please click through to install recommendations to complete this tutorial.
• Run project
  • Open Terminal (Ctrl+Shift+' or Menu->Terminal->New Terminal)
  • dotnet run
• Check project output and view the site root (e.g. http://localhost:5094/)
• Open main code file Program.cs

• Modify default "/" method to return "Welcome to Hello .NET"
• Add additional handler for "/hello" to return "Hello World!"
• Stop and run project e.g. ctrl+c in terminal then dotnet run again
• View updated site
  • Check /
  • Check /hello You should see the updated responses
• Add a method to return an example object

app.MapGet("/json", () => new { example=123, myString="This is a string", source=nameof(app) });

• Restart the server again and check "/json" endpoint

• Below app.MapGet(...) calls and above app.Run() add the following function

IResult MyCustomEndpoint()
{
	var myDictionary = new Dictionary<string,dynamic>();
	myDictionary.Add("anInteger", 123);
	myDictionary.Add("aString", "Example string");
	myDictionary.Add("now", DateTime.UtcNow);
	myDictionary.Add("nowString", DateTime.UtcNow.ToString("yyyy-MM-dd mm:HH:ss"));
        myDictionary.Add("compositeString", $"Now={DateTime.UtcNow:yyyy-MM-dd}, Count={myDictionary.Keys.Count}");
        return Results.Ok(myDictionary);
}

• Add another endpoint (in existing MapGet block):

app.MapGet("/custom", MyCustomEndpoint);

• Restart and test /custom endpoint

• Create a folder called "Interfaces"
• Right click the folder and select "New C# Interface"
  • Call it IMyService
• Shorten namespace declaration and add example GetDataMethod by replacing it's body/content with this:

namespace HelloNet.Interfaces;
public interface IMyService
{
    string GetData();
}

• Create a Services folder, right click and select "New C# Class"
  • Call it MyService
• Amend MyService to the following:

namespace HelloNet.Services;
public class MyService : IMyService
{
}

• You should see that IMyService has a red squiggly line underneath it showing an issue
  • Move the cursor to IMyService and press ctrl+. then select using HelloNet.Interfaces
    • This inserts the required using HelloNet.Interfaces; line at the top, which you could have entered manually but useful to know this technique too.
• You should now see the colour of IMyService has changed to match other names, but that it still has a red squiggly line showing another issue
  • Again select and use ctrl+., this time selecting Implement interface
• That will have generated out a template method with a NotImplementedException, so we will replace that with this short lambda version:

public string GetData() => $"Called {nameof(GetData)} in instance of {nameof(MyService)}";

• Add the following endpoint to the current MapGet block:

app.MapGet("/services", (IMyService service) => service.GetData());

• Again you'll have a red squiggly line, use ctrl+.->using ... or add using HelloNet.Services; to the top of Program.cs to resolve the missing reference.
• Restart project and you'll find it complains with

Unhandled exception. System.InvalidOperationException: Body was inferred but the method does not allow inferred body parameters.
Below is the list of parameters that we found:

Parameter           | Source
---------------------------------------------------------------------------------
service             | Body (Inferred)


Did you mean to register the "Body (Inferred)" parameter(s) as a Service or apply the [FromService] or [FromBody] attribute?

This is because we have no registered anything of type IMyService so it isn't connecting this to out implementation...

• After var builder = WebAppllication.CreateBuilder(args); and before var app = builer.Build(); add the following builder.Services.AddSingleton<IMyService,MyService>();
• Resolve the missing dependency with ctrl+. or by adding using HelloNet.Services
• Restart and view /services

• Add the myData property to appsettings.json e.g.

{
	...
	"myData": "This is from appsettings.json"
	...
}

• Update MyService to use this value by replacing the GetData method with the following:

    protected IConfiguration Configuration;
    public MyService(IConfiguration configuration)
    {
        Configuration = configuration;
    }
    public string GetData() => Configuration.GetValue<string>("myData");

• Restart and refresh /services
• Set myData in appsettings.Development.json to "This is from appsettings.Development.json"
• Restart and refresh /services ... you will see the new value, as when running in development environment this file takes precedence over base values from appsetings.json