c# groupbox 标题居中，并修改边框颜色

private void groupBox1_Paint(object sender, PaintEventArgs e) {
e.Graphics.Clear(groupBox1.BackColor);
SizeF fontSize = e.Graphics.MeasureString(groupBox1.Text, groupBox1.Font);
e.Graphics.DrawString(groupBox1.Text, groupBox1.Font, Brushes.MediumBlue, (groupBox1.Width - fontSize.Width) / 2, 1);
e.Graphics.DrawLine(Pens.MediumBlue, 1, 10, (groupBox1.Width - fontSize.Width) / 2, 10);
e.Graphics.DrawLine(Pens.MediumBlue, (groupBox1.Width + fontSize.Width) / 2 - 4, 10, groupBox1.Width - 2, 10);
}