//窗体上添加一个pictureBox，双击paint事件，内部代码如下
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
Bitmap bmp = new Bitmap(e.ClipRectangle.Width,e.ClipRectangle.Height);
Graphics g = Graphics.FromImage(bmp);
Pen penColor = new Pen(Color.Tomato,2);
g.DrawArc(penColor, e.ClipRectangle, 0, 360);
e.Graphics.DrawImage(bmp, new Point(0, 0));
bmp.Save("C:\\Temp.bmp");
}