Pen p1 = new Pen(Color.LightGray);
            p1.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;
 
            Pen p2 = new Pen(Color.LightGray);
            p2.DashStyle = System.Drawing.Drawing2D.DashStyle.Dot;
 
            if (this.ShowGrid)
            {
                for (int i = 19; i < ClientSize.Height; i += 20)
                {
                    if ((i + 1) % 40 == 0)
                    {
                        e.Graphics.DrawLine(p1, 0, i, ClientSize.Width, i);
                    }
                    else
                    {
                        e.Graphics.DrawLine(p2, 0, i, ClientSize.Width, i);
                    }
                }
 
                for (int i = 19; i < ClientSize.Width; i += 20)
                {
                    if ((i + 1) % 40 == 0)
                    {
                        e.Graphics.DrawLine(p1, i, 0, i, ClientSize.Height);
                    }
                    else
                    {
                        e.Graphics.DrawLine(p2, i, 0, i, ClientSize.Height);
                    }
                }
            }

Robert Blutner
robertblutner.de