OpenMCDF is a free structured storage component for .net. MPL licensed, full source included.
OpenMCDF is a 100% managed .net component that allows client applications to manipulate COM structured storage files, also known as Microsoft Compound Document Format files.
OpenMCDF makes available to the developer an easy interface to read, write, add and remove structured storage primitives. Items are organized in a hierarchical tree where 'storage' nodes act like a directory and 'stream' nodes like a file. Developers can use OpenMCDF to view storages and streams, traverse hierarchical trees of items, explore existing compound file and modify them or create a new compound file from scratch.