.NET Core Dependency Injection with Func as constructor parameter

This post will be short and sweet, albeit one that caused me a bit of a headache. I recently worked on an ASP.NET Core project and I wanted to take advantage of the built-in Dependency Injection service to inject various services to the controllers. However, one of the services required a parameter in the constructor; to be more exact I was asked to create a unit of work for all the different zones that we have but the connection has to change for each region so this is the solution I came up with:

	using Microsoft.Extensions.DependencyInjection;
	string appConnection = "MyConnectionString";
	string ConnectionStringProvider() => appConnection;
	var services = new ServiceCollection();
	services.AddTransient<IMyService>(s => new MyService(ConnectionStringProvider));
	var provider = services.BuildServiceProvider();
	var myService = provider.GetService<IMyService>();
	Console.WriteLine($"The constructor parameter is: {myService?.ExecuteMyMostAwesomeSelectWithTheGivenConnection()}");
	appConnection = "MyNewConnectionString1";
	Console.WriteLine($"The constructor parameter is: {myService?.ExecuteMyMostAwesomeSelectWithTheGivenConnection()}");
	Console.ReadKey();
	public interface IMyService
	{
	string GetConstructorParameter();
	}
	public class MyService : IMyService
	{
	private readonly Func<string> _connectionString;
	public MyService(Func<string> connectionStringProvider)
	{
	this._connectionString = connectionStringProvider;
	}
	public string ExecuteMyMostAwesomeSelectWithTheGivenConnection()
	{
	return _connectionString();
	}
	}

view raw Program.cs hosted with ❤ by GitHub

The important magick is here:

	var myService = provider.GetService<IMyService>();
	Console.WriteLine($"The constructor parameter is: {myService?.ExecuteMyMostAwesomeSelectWithTheGivenConnection()}");
	appConnection = "MyNewConnectionString1";
	Console.WriteLine($"The constructor parameter is: {myService?.ExecuteMyMostAwesomeSelectWithTheGivenConnection()}");

view raw Program.cs hosted with ❤ by GitHub