C# 如何从已包含文本的标签中减去数字

enemyHP.Text=敌人HP:+rat.HP.ToString

既然里面有文字，我该怎么做呢。我只想让它每秒钟下降一次

    private void battleButton_Click(object sender, EventArgs e)
    {
        if (battleDropBox.SelectedItem.ToString() == "Rat")
        {
            enemyHP.Text = "Enemy HP: " + rat.HP.ToString();
            enemyDPS.Text = "Enemy DPS: " + rat.Damage.ToString();


            timer.Tick += new EventHandler(timer1_Tick);
            timer.Interval = 1000;
            timer.Start();
        }
    }

    private void timer1_Tick(object sender, EventArgs e)
    {
        dealDamage();
    }

    public void dealDamage()
    {
    }

您应该减小rat.HP值，然后更新标签

public void dealDamage()
{
    rat.HP--;
    enemyHP.Text = "Enemy HP: " + rat.HP.ToString();
}

dealDamage什么都没做。。。