private void bindNonUserList()
{
string beginning = beginTextBox.Text;
Tuple <bool, List <string> > tuple = controller.getRestUsers(username, beginning);
if (!tuple.Item1)
{
Utils.Instance.errorAndExit("Error trying to access users records");
}
users = tuple.Item2;
userList.ItemsSource = null;
userList.ItemsSource = users;
}