Listing Workshop Items
At some point you'll probably want to grab a list of workshop items to show to your players. This could be anything from addons, maps, screenshots, saved games, demo files etc. Valve don't specify what they upload - you do.
Queries
I've tried to make things easy and hopefully as a c# user it'll seem familar.
The following queries screenshots that have been created by your friends.
This is the same except they're sorted by creation date
This is the same except tagged "funny"
Item Types
The types correspond to the enum EUGCMatchingUGCType. Valve does a good job of explaining the categories there.
So you can search all items with ak47 in the title/description like:
Conditional
The query doesn't have to be created on one line
Pages
Results are returned in pages. And the page number starts at 1.