Which API can I use for writing SDL Tridion workflow activities?

Question

I would like to create workflow using SDL Tridion 2011 SP1, and i am going through the documentation in the live content portal.

I have few questions when I go throu

Answer 1

Can I use C# (TOM.NET) for automated activities? Or should I use only VBScript (TOM)?

You can use the TOM within your C# code to write automated activities. There is a primary interop assembly provided for that purpose (IIRC).

Is use of TOM.NET allowed in workflows?

Accessing workflow items from within existing TOM.NET code (i.e. a TBB or DataExtender) is supported. So you can query items that are in workflow, kick off workflows, etc.. But using the TOM.NET for writing automated workflow activities is not supported.

The reason for this has something to do with incompatible threading models from what I recall. But I mostly just took the word of the developers for it; they are bound to know better than me.

Where can I get code/TOM API reference?

API reference documentation for Tridion is not in LiveContent, but instead is delivered in CHM (or zipped JavaDoc) files. The latest documentation for the TOM API can be found in the "SDL Tridion 2009 full documentation" zip on the Tridion 2009 documentation page on SDL Tridion World (login required).

Thanks to Quirijn and Alvin for pointing this out in the comments.