private async Task ShowAnnotation()
 {
     var model = new ValidatableModel();
     using (var viewModel = GetViewModel<DataAnnotationViewModel>())
     {
         viewModel.Model = model;
         viewModel.AddInstance(model);
         await viewModel.ShowAsync();
     }
 }
 public DataAnnotationViewModel()
 {
     //Initialize empty value, to avoid null references in properies.
     Model = new ValidatableModel();
 }