动画显示窗体

实现效果：

　　　　

知识运用：

　　API函数AnimateWindows

　　[DllImportAttribute("user32.dll")]
　　private static extern bool AnimateWindow(IntPtr hwnd,int dwTime,int dwFlags);

1. hwnd: IntPtr,窗口句柄
2. dwTime：动画的持续时间
3. dwFlags：动画类型选项　常量值如下

　　

实现代码：　

        private const int AW_SLIDE = 0x00040000;
        private const int AW_VER_NEGATIVE = 0x00000008;
        private const int AW_HIDE = 0x00010000;
        public Form1()
        {
            InitializeComponent();
            AnimateWindow(this.Handle, 3000, AW_SLIDE + AW_VER_NEGATIVE);   //开始窗体动画
        }
        [DllImportAttribute("user32.dll")]
        private static extern bool AnimateWindow(IntPtr hwnd,int dwTime,int dwFlags);   //重写API函数用来执行窗体动画显示操作
        
        //绘制渐变背景  
        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            Color sColor = Color.Green; //颜色1，2
            Color eColor = Color.Black;
            //实例化刷子  (上色域 开始色 结束色 颜色方向)
            Brush b = new LinearGradientBrush(this.ClientRectangle,sColor,eColor,LinearGradientMode.Vertical);
            g.FillRectangle(b,this.ClientRectangle);    //进行上色
        }

        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            AnimateWindow(this.Handle, 3000, AW_SLIDE + AW_VER_NEGATIVE+AW_HIDE);   //结束窗体动画
        }