好象没法创建Graphics的实例，但是我用以下这个办法可以解决，你看成不？
private void b_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
Pen p = new Pen(Color.Red, 3);
e.Graphics.DrawArc(p, 1,1,100,100,45,270);
}
private void button2_Click(object sender, System.EventArgs e)
{
//button1.Paint -= new System.Windows.Forms.PaintEventHandler(this.button1_Paint);
button1.Paint += new PaintEventHandler(b_Paint);
button1.Refresh();
}
