private void create(object sender, RoutedEventArgs e)
 {
     if (playListValidation.isAllFieldValidate() && ((PlayList)controller.complete(TextCommand.READ_PLAY_LIST_BY_NAME, playList.Name)) == null)
     {
         playList.UserId = user.Id;
         controller.complete(TextCommand.CREATE_PLAY_LIST, playList);
         back(sender, e);
     }
     else
     {
         MessageBox.Show("Wrong fields or play list already exist");
     }
 }