Detect when datagrid is filtered

Is there a property of the datagrid that can be used to determine if the grid is currently being filtered or not? I know there is a minor cosmetic change to the filter but my end users are looking for something a little more obvious such as a a tool tip whenever a filter is on. Is it possible to determine this? Thanks in advance!

The easiest way will be to check grid.View.Count() vs grid.Data.Count(). If view count is less than data count the grid is filtered.

Thanks, this would definitely work! However, how would I be able to detect that the filter was applied? Is there a datagrid method I can call to notify that the state has changed?