C#GDI画立体渐变圆角panel

为要处理的panel添加绘画事件，代码写在panel的Paint事件中：

 private void panel1_Paint(object sender, PaintEventArgs e)         {

            //（new 一个矩形，范围为panel的上半部分）

            Rectangle rt1 = new Rectangle(0, 0, panel1.Width, (panel1.Height/2));

            //（new一个渐变笔刷，渐变范围为上面新建的矩形，即panel的上半部分，渐变色从白色到蓝色，渐变角度LinearGradientMode.Vertical为垂直渐变）             LinearGradientBrush br = new LinearGradientBrush(rt1, Color.White, Color.Blue,   LinearGradientMode.Vertical);             Graphics g = e.Graphics;//为控件创建Graphics             g.FillRectangle(br, rt1);//填充矩形

//(下面同上面的操作，渐变panel的下半部分)             LinearGradientBrush br2 = new LinearGradientBrush(rt1, Color.Blue, Color.White, LinearGradientMode.Vertical);             Rectangle rt2 = new Rectangle(0,(panel1.Height/2), panel1.Width, panel1.Height/2);             g.FillRectangle(br2, rt2);

            //实现圆角形状的panel             List list = new List();//建立点集合list             int width = this.panel1.Width;             int height = this.panel1.Height;             //panel左上的点             list.Add(new Point(0, 4));             list.Add(new Point(1, 4));             list.Add(new Point(1, 3));             list.Add(new Point(2, 2));             list.Add(new Point(3, 1));             list.Add(new Point(4, 1));             list.Add(new Point(4, 0));             //panel右上的点             list.Add(new Point(width - 4, 0));             list.Add(new Point(width - 4, 1));             list.Add(new Point(width - 3, 1));             list.Add(new Point(width - 2, 2));             list.Add(new Point(width - 1, 3));             list.Add(new Point(width - 1, 4));             list.Add(new Point(width - 0, 4));             //panel右下角的点             list.Add(new Point(width - 0, height - 4));