增加窗体边框3D效果

 /// <summary>

        /// 增加窗体边框3D效果

        /// </summary>

        /// <param name="e"></param>

        protected override void OnPaint(PaintEventArgs e)

        {

            base.OnPaint(e);

            using (Pen bluePen = new Pen(Color.FromArgb(, , )))

            {

                e.Graphics.DrawLine(bluePen, , , this.Width - , );

                e.Graphics.DrawLine(bluePen, , , , this.Height - );

                e.Graphics.DrawLine(bluePen, , this.Height - , this.Width - , this.Height - );

                e.Graphics.DrawLine(bluePen, this.Width - , , this.Width - , this.Height - );

            }

        }