Caliburn Micro : injection in ViewModel problem

gistfile1.cs

 public class AppBootstrapper : BootstrapperBase {
 
 ...
 
         protected override void Configure() {
            container = new SimpleContainer();
            container.Instance(container);
            container.Singleton<IWindowManager, WindowManager>();
            container.Singleton<IEventAggregator, EventAggregator>();
            container.PerRequest<ShellViewModel>();
            container.PerRequest<IRepository<Worklist>, DBRepository<Worklist>>()
            ...
          }
 }
 
 public class WorklistViewModel : Screen   {
 ...
      public WorklistViewModel(IRepository<Worklist> worklistRepository)
        {
        ...
        }
 
 }