2nd may please see archive for visual studio 2010 intellisense ardupilot overview

The visual micro addin provides intellisense using visual studio for all arduino core, library and your own project files

If you add or link your own files to a visual micro project and the intellisense doesn't detect them. Just click compile on the tool bar (or rebuild the vs project)

Click CTRL+J in your code to see a master list of properties. See example...

When switching board, when adding an arduino library or when you add or link multiple existing files to a project you will see the background progress for the intellisense update

If your arduino intellisense stops working (somestimes happens with visual studio) then shutdown visual studio and delete the .ncb file of the project (it's in the projects folder). Important - Only delete the .ncb!