Skylight example C# code

MainPageViewModel.cs

using TestApp.Views;
using Skylight;
using Skylight.Common;
using Skylight.Messaging;
using Windows.ApplicationModel.Activation;
using Windows.Storage.Pickers;
using Windows.UI.Popups;

namespace TestApp.ViewModels
{
    public class MainPageViewModel : ViewModel,
        INavigationStateProvider,
        IContinuable<FileOpenPickerContinuationEventArgs>,
        IContinuable<FileSavePickerContinuationEventArgs>
    {
        public void LoadNavigationState(WrappedLoadStateEventArgs args)
        {
        }

        public void SaveNavigationState(WrappedSaveStateEventArgs args)
        {
        }

        public async void ButtonClicked()
        {
            var resp = await this.Messenger.GetResponseAsync(new MessageDialogMessage(
                "File Pick Test", "Test Dialog",
                new UICommand("OpenPicker"), new UICommand("SavePicker")));
            if (resp.ResultIndex == 0)
            {
                var picker = new FileOpenPicker
                {
                    ViewMode = PickerViewMode.Thumbnail,
                    SuggestedStartLocation = PickerLocationId.PicturesLibrary
                };
                picker.FileTypeFilter.Add(".png");
                picker.FileTypeFilter.Add(".gif");
                picker.FileTypeFilter.Add(".jpg");
                picker.PickSingleFileAndContinue();
            }
            else
            {
                var picker = new FileSavePicker
                {
                    SuggestedFileName = "photo1",
                    SuggestedStartLocation = PickerLocationId.PicturesLibrary,
                };
                picker.FileTypeChoices.Add("Photo File", new[] { ".png", ".gif", ".jpg" });
                picker.PickSaveFileAndContinue();
            }
        }

        public async void Continue(FileOpenPickerContinuationEventArgs args)
        {
            if (args.Files.Count > 0)
            {
                var file = args.Files[0];
                await this.Messenger.GetResponseAsync(new MessageDialogMessage(
                    "opening file: " + file.Name + " | " + file.Path, "Opening file"));
            }
            else
            {
                await this.Messenger.GetResponseAsync(new MessageDialogMessage(
                    "Cancelled!", "Opening file"));
            }
        }

        public async void Continue(FileSavePickerContinuationEventArgs args)
        {
            if (args.File != null)
            {
                var file = args.File;
                await this.Messenger.GetResponseAsync(new MessageDialogMessage(
                    "saving file: " + file.Name + " | " + file.Path, "Saving file"));
            }
            else
            {
                await this.Messenger.GetResponseAsync(new MessageDialogMessage(
                    "Cancelled!", "Saving file"));
            }
        }

        public void Loaded()
        {
        }

        public async void BeginAuth()
        {
            await this.Messenger.RaiseAsync(new NavigationMessage(typeof(AuthenticationPage)));
        }

        public bool IsButtonEnabled
        {
            get { return true; }
        }
    }
}