public void ConfigureServices(IServiceCollection services)
{
// Add browser detection services.
    services.AddDetection()
                 .AddDevice();
.AddBrowser()   // concept
.AddEngine()    // concept
.AddPlatform(); // concept

    // Add framework services.
    services.AddMvc();
}

public class HomeController : Controller
{    
    private readonly IUserAgent _useragent;    
    private readonly IBrowser _browser;
    private readonly IEngine _engine;
    private readonly IPlatform _platform;
private readonly IUserAgent _useragent;
    private readonly IDevice _device; 

    public HomeController(IBrowserResolver browserResolver, 
        IEngineResolver engineResolver, IDeviceResolver deviceResolver,
        IPlatformResolver platformResolver)
    {
        _useragent = browserResolver.UserAgent,        
        _browser = browserResolver.Browser,
        _engine = engineResolver.Engine,
        _platform = platformResolver.Platform
        _useragent = deviceResolver.UserAgent,
        _device = deviceResolver.Device
    }

    public IActionResult Index()
    {            
        return View();
    }
}