Stylet.StyletInvalidViewTypeException

Hello. I get this exception says that View doesn’t derive from the Window class. But I call .ShowDialog from Conductor<IScreen>.Collection.OneActive derives from Window. Window’s ViewModel:

public class MainViewModel : Conductor<IScreen>.Collection.OneActive
    {
        private ErrorBoxViewModel errorBox;
        private readonly IWindowManager windowManager;

        public MainViewModel(IWindowManager windowManager)
        {
            this.windowManager = windowManager;
        }

        public void ShowError(string message)
        {
            if (errorBox != null)
                errorBox.RequestClose();
            errorBox = new ErrorBoxViewModel(message);
            this.windowManager.ShowDialog(errorBox);
        }
    }

In another view model derives from UserControl I call: (Conductor as MainViewModel).ShowError("some string");

ErrorBoxViewModel view model derives from UserControl as well:

public class ErrorBoxViewModel : Screen
    {
        public string Message { get; private set; }

        public ErrorBoxViewModel(string message)
        {
            this.Message = message;
        }

        protected override void OnActivate()
        {
            base.OnActivate();
        }

        protected override void OnDeactivate()
        {
            base.OnDeactivate();
        }

        public void CloseWithSuccess()
        {
            this.RequestClose(true);
        }
    }

Any Idea what’s wrong?

[canton7]

So not as a Window at all?

You’ll want to put both the TabControl and the overlay in the same Grid, so that the overlay is placed on top of the TabControl. Something like this (untested, might have errors):

<Window x:Class="Your.MainView" ....>
    <Grid>
        <!-- Display both the overlay and the TabControl, with the overlay on top of the TabControl -->
        <TabControl .....>
        </TabControl>
        <ContentControl s:View.Model="{Binding Overlay}"/>
    </Grid>
</Window>

public class MainViewModel : Conductor<IScreen>.Collection.OneActive
{
    private IScreen _overlay;
    public IScreen Overlay
    {
        get { return this._overlay; }
        private set { this.SetAndNotify(ref this._overlay, value); }
    }

    public void ShowOverlay()
    {    
        this.Overlay = new SomeViewModel();
    }
}

[canton7]

Cool!