I am developing a WinForms application and would like to integrate help into it. In the past I integrated .chm help files.
Regarding .chm files, this Wiki article states:
In 2002, Microsoft announced security risks associated with the .CHM format, as well as security bulletins and patches. They have since announced their intentions not to develop the .CHM format further.
From what I have read, Microsoft Help 2.x was the help engine used in VS 2008 and Office 2007 using .hxs file extension help files.
What is used in Office 2010? What is the recommended help file format to be used?
Update:
I found the following MSDN article with helpful information on this topic:
Sandcastle - http://sandcastle.codeplex.com/ - is widely used. It has multiple output formats, including the generation of a website which you could publicly or privately host for your application users, allowing you to make updates as needed without needing to roll out new help files to all users individually.
You can also use Sandcastle to generate files which integrate with the MS help file viewer built into Windows. I don't know if this is "officially" the best method, but it works well.
The only caveat with Sandcastle is that it has a bit of a learning curve.
Also of interest: http://en.wikipedia.org/wiki/Microsoft_Assistance_Markup_Language. MAML defines a common schema for describing a very wide variety of help/documentation scenarios. MAML allows you to document end user functionality as well as API-level tasks. Depending on your audience, this may be of significant value. Sandcastle includes many MAML templates.