打字游戏代码。。。。

private void Form1_Load(object sender, EventArgs e)
        {
            this.timer1.Interval = 500;
            this.timer1.Start();
        }


        Random r = new Random();
        private void timer1_Tick(object sender, EventArgs e)
        {
            Label l = new Label();
            char cc = (char)((int)'A' + r.Next(26));
            l.Text = cc.ToString();
            l.Left = r.Next(this.Width);
            this.Controls.Add(l);

            foreach (Control c in this.Controls)
            {
                c.Top += 15;
                if (c.Top == this.Height) c.Dispose();
            }
        }

        private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            foreach (Control c in this.Controls)
            {
                if (c.GetType() == typeof(Label))
                {
                    Label t = (Label)c;