Specifies the portion of the tick mark on the outside of the grid.
The TickLength property, along with the
InnerLength property, specify the length of tick marks in pixels that are drawn at the major grid interval. The InnerLength property specifies the length of the tick mark on the inside of the chart area. If either the TickLength property or the InnerLength property is greater than 0 and doDrawTickMarks is in
DrawOptions, then a tick mark on the major grid interval is drawn.