给段代码自己看看吧 画一个饼状图，相关方法查帮助 。
void Page_Load(Object sender, EventArgs e) {
Bitmap bm=new Bitmap(200,200);
Graphics g=Graphics.FromImage(bm);
g.Clear(Color.Yellow);
Pen p=new Pen(Color.Black,1);
Rectangle rect=new Rectangle(10,10,180,180);
g.DrawEllipse(p,rect);
Brush b1=new SolidBrush(Color.Red);
g.FillPie(b1,rect,0f,190f);
Brush b2=new SolidBrush(Color.Green);
g.FillPie(b2,rect,190f,70f);
Brush b3=new SolidBrush(Color.Blue);
g.FillPie(b3,rect,260f,100f);
bm.Save(Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);
}