void _add_files(object param)
 {
     Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();
     if (dlg.ShowDialog() == true)
     {
         foreach (String file in dlg.FileNames)
         {
             if (File_list == null)
             {
                 File_list = new ObservableCollection <Model.Card.File>();
             }
             Model.Card.File a = new Model.Card.File(file.Split('\\')[file.Split('\\').Length - 1], file);
             File_list.Add(a);
             ad.Add(a);
         }
     }
 }
 void _del_files(object param)
 {
     File_list.Remove(selected_file);
     del.Add(selected_file);
     //((App)App.Current).all_data.delete_file(that_card.Id,selected_file);
 }