private async void ExecuteRunExtendedDialog(object o)
        {
            //let's set up a little MVVM, cos that's what the cool kids are doing:
            var view = new SampleDialog
            {
                DataContext = new object()
            };

            //show the dialog
            var result = await DialogHost.Show(view, "RootDialog", ExtendedClosingEventHandler);

            //check the result...
            Console.WriteLine("Dialog was closed, the CommandParameter used to close it was: " + (result ?? "NULL"));
        }
        private async void ExecuteRunExtendedDialog(object o)
        {
            //let's set up a little MVVM, cos that's what the cool kids are doing:
            var view = new SampleDialog
            {
                DataContext = new object()
            };

            //show the dialog
            var result = await DialogHost.Show(view, "RootDialog", ExtendedClosingEventHandler);

            //check the result...
            Console.WriteLine("Dialog was closed, the CommandParameter used to close it was: " + (result ?? "NULL"));
        }