Add project files.

WinGreedWPF/StartupHelpers/ServiceExtensions.cs

@@ -0,0 +1,15 @@
+using Microsoft.Extensions.DependencyInjection;
+using System;
+
+namespace WinGreedWPF.StartupHelpers;
+
+public static class ServiceExtensions
+{
+    public static void AddFormFactory<TForm>(this IServiceCollection services)
+        where TForm : class
+    {
+        services.AddTransient<TForm>();
+        services.AddSingleton<Func<TForm>>(x => () => x.GetService<TForm>()!);
+        services.AddSingleton<IAbstractFactory<TForm>, AbstractFactory<TForm>>();
+    }
+}