窗体特效—弹出时慢慢从透明到不透明的特效

利用Timer+Opacity来实现：

 

private double opacityIncrement = 0.1;
        private const int changeInterval = 25;
        private Timer timer1;

        //表单载入
        private void Form1_Load(object sender, System.EventArgs e)
        {

            timer1=new Timer();
            timer1.Interval=changeInterval;
            timer1.Tick+=new System.EventHandler(this.timer1_Tick);
            this.Opacity=0;
            timer1.Start();
        }

        //渐显事件
        private void timer1_Tick(object sender, System.EventArgs e)
        {
             this.timer1.Stop();
            if(this.Opacity<1)
            {
                this.Opacity=this.Opacity+this.changeInterval;
            }
            else
            {
                this.timer1.Enabled=false;
            }
               this.timer1.Start();
        }