C# Window_KeyUp() not working

C# Window_KeyUp() not working

Hey I have this piece of code:
private void Window_KeyUp(object sender, KeyEventArgs e)
{
    if (playing == false)
    {
        return;
    }
    if (e.KeyCode == Keys.D1)
    {
        pictureBox6.Image = Form.Properties.Resources.black_square_button;
        player.Stop();
        player.Close();
        playing = false;
    }
}
I'ts not working but the Window_KeyDown() works.
What is wrong with my code?
Thanks.