private void SaveToJsonFile_Click(object sender, RoutedEventArgs e) { SaveFileDialog dlg = new SaveFileDialog(); dlg.DefaultExt = ".json"; // Default file extension dlg.Filter = "JSON files (.json)|*.json"; // Filter files by extension bool?result = dlg.ShowDialog(); if (result == true) { string fileName = dlg.FileName; Dictionary <string, IEnumerable <string> > dict = TreeModel <string> .LayerToDictionary(RegexTitleTreeView.SaveToTreeModel()); File.WriteAllText(fileName, Serializer.Serialize(dict)); } }