TrackArrangeOverride 方法

Children will be stretched to fit horizontally (if vertically oriented) or vertically (if horizontally oriented). There are essentially three possible layout states: 1. The track is enabled and the thumb is proportionally sizing. 2. The track is enabled and the thumb has reached its minimum size. 3. The track is disabled or there is not enough room for the thumb. Track elements are not displayed, and will not be arranged.

protected override Size ArrangeOverride(
	 in Size arrangeSize
)