Hi Mark Li,
Thank you for contacting Syncfusion Support.
We have analyzed your query. You cannot get the dependent cells when the cells are hidden, since hidden cells will not be considered while validating, hence if you could update us with the details of your requirement or the sample which explains your requirement, we will provide you a better solution. Please find the below sample which provides you a dependent cells list when you modify a cell value.
Sample link: http://www.syncfusion.com/downloads/support/forum/119643/ze/WpfApplication4-589034176
Please let us know if you have any queries.
Thanks
Kanimozhi B