private static LinkViewModel GetLinkViewModel(ViewModelBase viewModel)
{
if (viewModel is LinkedPictureViewModel)
return ((LinkedPictureViewModel)viewModel).ParentLink;
else if (viewModel is ReadableArticleViewModel)
return ((ReadableArticleViewModel)viewModel).ParentLink;
else if (viewModel is CommentsViewModel)
return ((CommentsViewModel)viewModel).Link;
else if (viewModel is LinkViewModel)
return ((LinkViewModel)viewModel).ParentLink;
else
throw new ArgumentException();
}