DI未向控制器注入服务

我有一个奇怪的情况。我在startup类中注册我的服务,如下所示

public void ConfigureServices(IServiceCollection services)
{
    ...
    services.AddSingleton<ISearchService, SearchService>();
    services.AddSingleton<IBrandSearchService, BrandSearchService>();
    services.AddSingleton<INearbySearchService, NearbySearchService>();
    services.AddSingleton<ILocationService, LocationService>();
    ...
}

但是,当我尝试在控制器的构造函数中访问它们时,即使我将其添加到构造函数参数中,或者尝试从ServiceCollection获取,它们也是空的

public class SuggestController
{
    readonly ILocationService locationService;

    public SuggestController(IOptions<SiteSettings> settings, IOptions<DBAccessBuilder> access, IStringLocalizer<SharedResources> localizer, IMemoryCache memoryCache, IHostingEnvironment environment)
    {
        this.locationService = (ILocationService)new ServiceCollection().BuildServiceProvider().GetService(typeof(ILocationService));
    }
}

实现ILocationService接口的My Location类

public class LocationService : ILocationService
{
    readonly ISolrOperations<LocationResult> search;

    ...

    public LocationService(ISolrOperations<LocationResult> search)
    {
        this.search = search;
    }

    ...
}

我错过了什么?