wpf comming back on a window code example

Example 1: wpf button to return to last window

private void Window1_Click(object sender, RoutedEventArgs e)
{
    Hide();
    new Window1().ShowDialog();
    ShowDialog();
}

Example 2: wpf button to return to last window

private void btn_Cancel_Click(object sender, RoutedEventArgs e)
{
    DialogResult = false;
}