How to Form.ShowDialog() using MVP and Passive Views?

Summary

I'm experimenting with the MVP pattern in a Windows Forms application.

I'd like to make both my Presenters and Views platform agnostic, so if I wish to port my application to another platform, say the Web or mobile, I simply need to implement the views with platform dependant GUI, and my presenters can still be platform independent.

And now I wonder, how to ShowDialog() using MVP and Passive Views?

To my understanding so far, passive views shouldn't know/care about any presenter. They don't even know it exists. So, the solution presented in this question's answer is not suitable, according to me: Refactoring Form.ShowDialog() code to MVP

Some code samples to help on the understanding:

ApplicationView

public partial class ApplicationForm : Form, IApplicationView {
    // I ensure that all the IApplicationView events are raised 
    // upon button clicks text changed, etc.
    // The presenter, which this view ignores the existence, 
    // is subscribed to the events this view raises.
}

ApplicationPresenter

public class ApplicationPresenter 
    : Presenter<IApplicationView>
    , IApplicationPresenter {
    public ApplicationPresenter(IApplicationView view) : base(view) {
        View.OnViewShown += OnViewShown;
    }

    public void OnViewShown() {
        IAuthenticaitonView authView = new AuthenticationForm();
        IAuthenticationPresenter authPresenter = new AuthenticationPresenter(authView);
        authPresenter.ShowDialog(); // 1.                       
    }
}

This is where I'm struggling. The ApplicationPresenter is like the master in the universer and may be aware of the user authentication through both the IAuthenticationView and IAuthenticationPresenter .

IAuthenticationView

public interface IAuthenticationView : IDialogView {
    string ErrorMessage { get; set; }
    string Instance { get; set; }
    IEnumerable<string> Instances { get; set; }
    string Login { get; set; }
    string Password {get; set; }

    void EnableConnectButton(bool enabled);

   event VoidEventHandler OnConnect;
   event SelectionChangedEventHandler OnDatabaseInstanceChanged;
   event VoidEventHandler OnLoginChanged;
   event VoidEventHandler OnPasswordChanged;
}

IDialogView

public interface IDialogView : IView {
    void ShowDialog();
}

IView

public interface IView { 
    void Show();

    event VoidEventHandler OnViewInitialize;
    event VoidEventHandler OnViewLoad;
    event VoidEventHandler OnViewShown;
}

IAuthenticationPresenter

public interface IAuthenticationPresenter : IPresenter<IAuthenticationView> {
    void OnConnect();
    void OnViewDatabaseInstanceChanged(SelectionChangedEventArgs e);
    void OnViewLoginChanged();
    void OnViewPasswordChanged();
}

IPresenter<V>

public interface IPresenter<V> where V : IView {
    V View { get; }

    OnViewInitialize();
    OnViewLoad();
    ShowView();
}

---

Based on these premisses:

The presenter shall be platform agnostic

Only the view knows how to show/display itself (WPF, Mobile, Silverlight, Web, WinForms...)

The view MUST provide a way to show itself

The view doesn't have to be platform agnostic , since the display will differ from a platform to another

But the presenter shall order the view when to show itself

I came to this:

IView

public interface IView {
    void OnShowView();
}

IPresenter<V>

public interface IPresenter<V>where V : IView {
    void ShowView();
    event VoidEventHandler OnShowView;
}

Presenter<V>

public abstract class Presenter<V> : IPresenter<V> {
    public Presenter(V view) { 
        View = view;
        OnShowView += View.OnShowView;
    }

    public void ShowView() { raiseShowViewEvent(); }

    public event VoidEventHandler OnShowView;

    private void raiseShowViewEvent() { if (OnShowView != null) OnShowView(); }
}

So, following the logic of where I struggled so far, I solved it by doing this:

ApplicationForm

public partial class ApplicationForm : Form, IApplicationView {
    private void ApplicationForm_Shown(object sender, EventArgs e) { raiseOnViewShown();  }            

    private void raiseOnViewShownEvent() { if (OnViewShown != null) OnViewShown(); }
}

ApplicationPresenter

public void OnViewShown() {
    // This method is the subscriber of the IView.OnViewShown event
    // The event is raised with the ApplicationForm_Shown event.
    IAuthenticationView authView = new AuthenticationForm();
    IAuthenticationPresenter authPresenter = new AuthenticationPresenter(authView);
    authPresenter.ShowView(); // 1.
}

This raises the OnShowView event which the IAuthenticationView has subscribed. Then, back in the form, the view's response to the event is:

AuthenticationForm

public partial class AuthenticationForm : Form, IAuthenticationView {
    public void OnShowView() { ShowDialog(); }
}

Then, the view shows itself as a dialog/modal window.

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