Is a .NET library for reading, manipulating and writing Excel 2007+ (.xlsx, .xlsm) files. It aims to provide an intuitive and user-friendly interface to dealing with the underlying OpenXML API.
https://github.com/ClosedXML/ClosedXML
There are multiple root elements
https://github.com/ClosedXML/ClosedXML/issues/894
origin - https://www.pipiscrew.com/?p=17284 closedxml