WinFormDiApp/WinFormDi/Program.cs

using DIDemoLib;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace WinFormDi
{
    internal static class Program
    {
        /// <summary>
        ///  The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            var host = ContainerConfig.Configure();
            using var scope = host.Services.CreateScope();

            try
            {
                var services = scope.ServiceProvider;

                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.SetHighDpiMode(HighDpiMode.SystemAware);

                var frm = services.GetRequiredService<MainWindow>();
                Application.Run(frm);
            }
            catch (Exception ex)
            {
                Console.WriteLine($"An error has occured: {ex.Message}");
            }

        }
    }
}