I want use offline MSDN documentation in my application.
Is there API for that ?
Check out similar question How to open .hxs Help files with DExplore.exe?
Microsoft Help 2.x is a proprietary format for online help files, developed by Microsoft and first released in 2001 as a help system for Visual Studio .NET (2002) and MSDN Library.
It's the help engine used in Microsoft Visual Studio 2002/2003/2005/2008 and Office 2007.
Visual Studio 2010 uses a new help engine, Microsoft Help Viewer
MS Help 3 Viewer replace the VS 2010 help viewer or run stand-alone.
Visual Studio 2010 Help Downloader for downloading base Visual Studio 2010 MSDN package for offline first installation.
Package This is a GUI tool written in C# for creating help files (.chm and .hxs) from the content obtained from the MSDN Library (MSHelp 2.0)