问题
Is there a way or an event to solve this? well specifically its for a flow layout panel
回答1:
If you're using a FlowLayoutPanel, you could check whether the Bottom property of the last control in the panel is more than the panel's height.
Alternatively, try checking VerticalScroll.Visible (I haven't tried that, but it shoud do what you're looking for)
来源：https://stackoverflow.com/questions/1522995/how-to-detect-when-the-scrollbars-appear-c-sharp