窗体渐变效果

 //加载时 timer控件运行一次
        private void InHosIndex_Load(object sender, EventArgs e)
        {
            timer1.Start();
        }
        //进入登录页面 有窗体的淡化效果
        private void timer1_Tick(object sender, EventArgs e)
        {

            //关闭timer
                timer1.Stop();
                //系统休眠0.2秒
                System.Threading.Thread.Sleep(200);
                      for (int i = 20; i > 0; i--)
                    {
                        //渐变的淡化效果
                        System.Threading.Thread.Sleep(50);
                        this.Opacity = Convert.ToDouble("0." + (i * 5 - 1).ToString().PadLeft(2, '0'));
                        Application.DoEvents();
                    }
                     //实例化login 窗体
                    Login lg = new Login();
                    lg.Show();
                    this.Hide();
              
             
        }