public  class ButtonX:Button     {                         protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)            {                base.OnPaint(e);                System.Drawing.Drawing2D.GraphicsPath path = new System.Drawing.Drawing2D.GraphicsPath();                path.AddEllipse(0, 0, this.Width, this.Height);                this.Region = new Region(path);                            }            protected override void onm ouseEnter(EventArgs e)            {                Graphics g = this.CreateGraphics();                g.DrawEllipse(new Pen(Color.Blue), 0, 0, this.Width, this.Height);                g.Dispose();            }                  }