将投向设置成圆形

        //将头像设置成圆角
        private void avatar_Paint(object sender, PaintEventArgs e)
        {
            
            GraphicsPath gp = new GraphicsPath();
            gp.AddEllipse(avatar.ClientRectangle);
            Region region = new Region(gp);
            avatar.Region = region;
            gp.Dispose();
            region.Dispose();
        }