public interface ILibraryDataManager
{
    //some code...
}
 
public class LibraryDataManager:ILibraryDataManager
{
     //some code...
}

interface IMessageService
{
     //some code
}
    class MessageService : IMessageService
{
     //some code
}

public interface ILoginService
{
    //some code
}
class LoginService : ILoginService
{  
     private readonly IMessageService messageServise;
     private readonly ILibraryDataManager libraryDBManger;
     public LoginService(IMessageService messageServise, ILibraryDataManager libraryDataManager)
     {
          this.messageServise = messageServise;
          this.libraryDBManger = libraryDataManager;
     }
        //some code...
}
 
public interface IMainService
{
     //some code
}
class MainService : IMainService
{     
    private readonly IMessageService messageService;
    private readonly ILibraryDataManager libraryDBManger;
 
    public MainService(ILibraryDataManager libraryDataManager, IMessageService messageService)
    {
         this.libraryDBManger = libraryDataManager;
          this.messageService = messageService;
     }
        //some code...
}

public interface IView
{
     //some code...
}
 
public interface ILoginView: IView
{
     //some code...      
}
 
public partial class FormLogin : Form, ILoginView
{
     //some code...
}
public interface IMainView: IView
{
     //some code...
}
 
public partial class MainForm : Form, IMainView
{
     //some code...
}

public interface IPresenter
{
    void Run(); // цей метод повинен запускати відповідну форму (IView), передану презентеру в конструкторі
}
 
class LoginPresenter : IPresenter
{
    private readonly ILoginView loginView;
    private readonly ILoginService loginService;
    private readonly IMessageService messageService;
 
    public LoginPresenter(ILoginView loginView, ILoginService loginService, IMessageService messageService)
    {
        this.loginView = loginView;
        this.loginService = loginService;
        this.messageService = messageService;
    }
    public void Run()
    {
        loginView.Show();
    }
    //some code...
}
 
class MainPresenter : IPresenter
{
    private readonly IMainView mainView;
    private readonly IMessageService messageService;
    private readonly IMainService mainService;
   
    public MainPresenter (IMainView mainView, IMessageService messageService, IMainService mainService)
    {
        this.mainService = mainService;
        this.mainView = mainView;
        this.messageService = messageService;
    }
 
    public void Run()
    {
        Application.Run(mainView as Form); 
    }

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
 
        UnityContainer container = new UnityContainer();
        container.RegisterType<ILibraryDataManager, LibraryDataManager>()
                    .RegisterType<IMessageService, MessageService>()
                    .RegisterType<ILoginService, LoginService>()
                    .RegisterType<ILoginView, FormLogin>()
                    .RegisterType<IMainView, MainForm>();
 
        var obj = container.Resolve<MainPresenter>();
        obj.Run();
    }
}