protected override Size ArrangeOverride(Size finalSize)
{
// 滚动区域相关逻辑
_scrollExtent = finalSize;
_canHorizontallyScroll = ExtentWidth > ViewportWidth;
_canVerticallyScroll = ExtentHeight > ViewportHeight;
_scrollOffset.X = CommonUtilities.Clamp(_scrollOffset.X, 0.0, ExtentWidth - ViewportWidth);
_scrollOffset.Y = CommonUtilities.Clamp(_scrollOffset.Y, 0.0, ExtentHeight - ViewportHeight);
if (ScrollOwner != null)
{
ScrollOwner.InvalidateScrollInfo();
}
base.InvalidateVisual();
return(base.ArrangeOverride(finalSize));
}