Closed Unassigned: cell selection [9319]

Hello,

I'm new to ClosedXML. I'm coding in X++ in Microsoft Dynamics AX.
My issue is that i'd need to get the first Cell and the last Cell regardless of number of columns and rows.
If somebody can help.

Thanks in advance.
Comments: worksheet.FirstCell() worksheet.LastCell() range.FirstCell() range.LastCell()