ExcelHelper/Utils/HostExtension.cs

using System.Reflection;
using ExcelHelper.Views;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace ExcelHelper.Utils;

internal static class HostExtension
{
    public static IHostBuilder AddViewAndViewModel(this IHostBuilder hostBuilder)
    {
        // Scan all assemblies to find all types that implement IViewModel
        var assem = Assembly.GetExecutingAssembly();
        var types = assem.GetTypes();
        foreach (var type in types)
        {
            if (type.IsInterface || type.IsAbstract)
            {
                continue;
            }
            if (typeof(IViewModel).IsAssignableFrom(type) || typeof(IView).IsAssignableFrom(type))
            {
                hostBuilder.ConfigureServices((context, services) =>
                {
                    services.AddSingleton(type);
                });
            }
        }
        return hostBuilder;
    }
}