getting the list of items shown by "app" tab in Task Manager is complex; it entails
finding the right window (i.e. knowing the names of the windows in its hierarchy),
then sending some LVM_... messages to the listview. It must be similar to enumerating
the notify icons in the system tray, and the icons on the desktop. Each of these
can be found in several CodeProject articles.
I dont think reading that list is a very good idea; it is complex and the names you would
get are Window titles, which does not necessarily correlate well with the process names...
Using TaskInfo I noticed the vshost.exe process has quite different characteristics
(CPU time, working set, number of windows, ...) when comparing an idle state with
an active debug state.
So if what you want to figure out is whether something is being handled by vshost,
I suggest you get hold of its PID (using Process class), then do a P/Invoke to
either get its main window title, or to enumerate all its windows (zero when not active).