Описание тега system.io.packaging
NoneSystem.io.packaging is Microsoft's system for creating and packaging complex multi-part documents. It is used by Microsoft Office for common formats like xlsx and docx, among others.
System.IO.Packaging is Microsoft's system for creating and packaging complex multi-part documents. It is used by Microsoft Office for common formats like xlsx and docx, among others.
The Package format is essentially a ZIPped folder with the document contents, the Parts, normally placed in subfolders in the ZIP. You can examine a Package by renaming it.zip and opening it, for instance, an xlsx file.
System.IO.Packaging can also be used as a basic ZIP library, but it will insist on adding a file at the root called [Content Types].xml.