private void Import_Click(object sender, RoutedEventArgs e) { TileManagerViewModel vm = DataContext as TileManagerViewModel; OpenFileDialog dialog = new OpenFileDialog() { Filter = "Collection package|*.col", AddExtension = true }; if (dialog.ShowDialog() == true) { CollectionSet imported = CollectionSet.ImportFromFile(dialog.FileName); vm.LoadedCollections.Add(imported); vm.SelectedCollection = imported; } }